diff --git a/Python/01_Image_Basics.ipynb b/Python/01_Image_Basics.ipynb
index 8df29a37..d2b1e58a 100644
--- a/Python/01_Image_Basics.ipynb
+++ b/Python/01_Image_Basics.ipynb
@@ -28,10 +28,10 @@
     "    import google.colab\n",
     "    import pathlib\n",
     "\n",
-    "    repo_dir = pathlib.Path(\"SimpleITK-Notebooks\")\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
     "    if not repo_dir.exists():\n",
     "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
     "    !pip install -q -r requirements.txt\n",
     "\n",
     "except ImportError:\n",
diff --git a/Python/02_Pythonic_Image.ipynb b/Python/02_Pythonic_Image.ipynb
index 9f0dfd17..6c6092c9 100644
--- a/Python/02_Pythonic_Image.ipynb
+++ b/Python/02_Pythonic_Image.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/03_Image_Details.ipynb b/Python/03_Image_Details.ipynb
index 483260d0..7a687cc5 100644
--- a/Python/03_Image_Details.ipynb
+++ b/Python/03_Image_Details.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/04_Image_Display.ipynb b/Python/04_Image_Display.ipynb
index 91cb5e03..77e9ac82 100644
--- a/Python/04_Image_Display.ipynb
+++ b/Python/04_Image_Display.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/05_Results_Visualization.ipynb b/Python/05_Results_Visualization.ipynb
index 4969dc0d..721e45ba 100644
--- a/Python/05_Results_Visualization.ipynb
+++ b/Python/05_Results_Visualization.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/10_matplotlibs_imshow.ipynb b/Python/10_matplotlibs_imshow.ipynb
index 17dfe13b..9ce1ae91 100644
--- a/Python/10_matplotlibs_imshow.ipynb
+++ b/Python/10_matplotlibs_imshow.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/11_Progress.ipynb b/Python/11_Progress.ipynb
index c059a61b..501e6023 100644
--- a/Python/11_Progress.ipynb
+++ b/Python/11_Progress.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/20_Expand_With_Interpolators.ipynb b/Python/20_Expand_With_Interpolators.ipynb
index 14bfee3c..2cc9dc9b 100644
--- a/Python/20_Expand_With_Interpolators.ipynb
+++ b/Python/20_Expand_With_Interpolators.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/21_Transforms_and_Resampling.ipynb b/Python/21_Transforms_and_Resampling.ipynb
index 18f56bd6..ec9c83c1 100644
--- a/Python/21_Transforms_and_Resampling.ipynb
+++ b/Python/21_Transforms_and_Resampling.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/22_Transforms.ipynb b/Python/22_Transforms.ipynb
index c459f803..1339469d 100644
--- a/Python/22_Transforms.ipynb
+++ b/Python/22_Transforms.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/300_Segmentation_Overview.ipynb b/Python/300_Segmentation_Overview.ipynb
index 87283135..dd011595 100644
--- a/Python/300_Segmentation_Overview.ipynb
+++ b/Python/300_Segmentation_Overview.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/30_Segmentation_Region_Growing.ipynb b/Python/30_Segmentation_Region_Growing.ipynb
index 9bcc791c..2beea88f 100644
--- a/Python/30_Segmentation_Region_Growing.ipynb
+++ b/Python/30_Segmentation_Region_Growing.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/31_Levelset_Segmentation.ipynb b/Python/31_Levelset_Segmentation.ipynb
index e9469b4f..0ec4614c 100644
--- a/Python/31_Levelset_Segmentation.ipynb
+++ b/Python/31_Levelset_Segmentation.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/32_Watersheds_Segmentation.ipynb b/Python/32_Watersheds_Segmentation.ipynb
index 3928821f..b5e7095b 100644
--- a/Python/32_Watersheds_Segmentation.ipynb
+++ b/Python/32_Watersheds_Segmentation.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/33_Segmentation_Thresholding_Edge_Detection.ipynb b/Python/33_Segmentation_Thresholding_Edge_Detection.ipynb
index a533524e..0f67cfcb 100644
--- a/Python/33_Segmentation_Thresholding_Edge_Detection.ipynb
+++ b/Python/33_Segmentation_Thresholding_Edge_Detection.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/34_Segmentation_Evaluation.ipynb b/Python/34_Segmentation_Evaluation.ipynb
index ada74379..8879f8f9 100644
--- a/Python/34_Segmentation_Evaluation.ipynb
+++ b/Python/34_Segmentation_Evaluation.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/60_Registration_Introduction.ipynb b/Python/60_Registration_Introduction.ipynb
index 3099e42f..ed1b9674 100644
--- a/Python/60_Registration_Introduction.ipynb
+++ b/Python/60_Registration_Introduction.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
@@ -53,28 +60,28 @@
     "### Optimizers\n",
     "\n",
     "Several optimizer types are supported via the `SetOptimizerAsX()` methods. These include:\n",
-    "* [Exhaustive](http://www.itk.org/Doxygen/html/classitk_1_1ExhaustiveOptimizerv4.html)\n",
-    "* [Nelder-Mead downhill simplex](http://www.itk.org/Doxygen/html/classitk_1_1AmoebaOptimizerv4.html), a.k.a. Amoeba\n",
-    "* [Powell optimizer](https://itk.org/Doxygen/html/classitk_1_1PowellOptimizerv4.html)\n",
-    "* [1+1 evolutionary optimizer](https://itk.org/Doxygen/html/classitk_1_1OnePlusOneEvolutionaryOptimizerv4.html)\n",
+    "* [Exhaustive](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1ExhaustiveOptimizerv4.html)\n",
+    "* [Nelder-Mead downhill simplex](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1AmoebaOptimizerv4.html), a.k.a. Amoeba\n",
+    "* [Powell optimizer](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1PowellOptimizerv4.html)\n",
+    "* [1+1 evolutionary optimizer](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1OnePlusOneEvolutionaryOptimizerv4.html)\n",
     "* Variations on gradient descent:\n",
-    "  * [GradientDescent](http://www.itk.org/Doxygen/html/classitk_1_1GradientDescentOptimizerv4Template.html)\n",
-    "  * [GradientDescentLineSearch](http://www.itk.org/Doxygen/html/classitk_1_1GradientDescentLineSearchOptimizerv4Template.html)\n",
-    "  * [RegularStepGradientDescent](http://www.itk.org/Doxygen/html/classitk_1_1RegularStepGradientDescentOptimizerv4.html)\n",
-    "* [ConjugateGradientLineSearch](http://www.itk.org/Doxygen/html/classitk_1_1ConjugateGradientLineSearchOptimizerv4Template.html)\n",
-    "* [L-BFGS2](https://itk.org/Doxygen/html/classitk_1_1LBFGS2Optimizerv4.html) (Limited memory Broyden, Fletcher, Goldfarb, Shannon)\n",
-    "* [L-BFGS-B](http://www.itk.org/Doxygen/html/classitk_1_1LBFGSBOptimizerv4.html) (Limited memory Broyden, Fletcher, Goldfarb, Shannon - Bound Constrained) - supports the use of simple constraints.\n",
+    "  * [GradientDescent](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1GradientDescentOptimizerv4Template.html)\n",
+    "  * [GradientDescentLineSearch](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1GradientDescentLineSearchOptimizerv4Template.html)\n",
+    "  * [RegularStepGradientDescent](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1RegularStepGradientDescentOptimizerv4.html)\n",
+    "* [ConjugateGradientLineSearch](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1ConjugateGradientLineSearchOptimizerv4Template.html)\n",
+    "* [L-BFGS2](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1LBFGS2Optimizerv4Template.html) (Limited memory Broyden, Fletcher, Goldfarb, Shannon)\n",
+    "* [L-BFGS-B](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1LBFGSBOptimizerv4.html) (Limited memory Broyden, Fletcher, Goldfarb, Shannon - Bound Constrained) - supports the use of simple constraints.\n",
     "\n",
     "\n",
     "### Similarity metrics\n",
     "\n",
     "Several metric types are supported via the `SetMetricAsX()` methods. These include:\n",
-    "* [MeanSquares](http://www.itk.org/Doxygen/html/classitk_1_1MeanSquaresImageToImageMetricv4.html)\n",
-    "* [Demons](http://www.itk.org/Doxygen/html/classitk_1_1DemonsImageToImageMetricv4.html)\n",
-    "* [Correlation](http://www.itk.org/Doxygen/html/classitk_1_1CorrelationImageToImageMetricv4.html)\n",
-    "* [ANTSNeighborhoodCorrelation](http://www.itk.org/Doxygen/html/classitk_1_1ANTSNeighborhoodCorrelationImageToImageMetricv4.html)\n",
-    "* [JointHistogramMutualInformation](http://www.itk.org/Doxygen/html/classitk_1_1JointHistogramMutualInformationImageToImageMetricv4.html)\n",
-    "* [MattesMutualInformation](http://www.itk.org/Doxygen/html/classitk_1_1MattesMutualInformationImageToImageMetricv4.html)\n",
+    "* [MeanSquares](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1MeanSquaresImageToImageMetricv4.html)\n",
+    "* [Demons](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1DemonsImageToImageMetricv4.html)\n",
+    "* [Correlation](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1CorrelationImageToImageMetricv4.html)\n",
+    "* [ANTSNeighborhoodCorrelation](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1ANTSNeighborhoodCorrelationImageToImageMetricv4.html)\n",
+    "* [JointHistogramMutualInformation](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1JointHistogramMutualInformationImageToImageMetricv4.html)\n",
+    "* [MattesMutualInformation](https://docs.itk.org/projects/doxygen/en/stable/classitk_1_1MattesMutualInformationImageToImageMetricv4.html)\n",
     "\n",
     "\n",
     "### Interpolators\n",
diff --git a/Python/62_Registration_Tuning.ipynb b/Python/62_Registration_Tuning.ipynb
index 3381013e..f2ca1741 100644
--- a/Python/62_Registration_Tuning.ipynb
+++ b/Python/62_Registration_Tuning.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/64_Registration_Memory_Time_Tradeoff.ipynb b/Python/64_Registration_Memory_Time_Tradeoff.ipynb
index 1a77fd83..de77706c 100644
--- a/Python/64_Registration_Memory_Time_Tradeoff.ipynb
+++ b/Python/64_Registration_Memory_Time_Tradeoff.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/67_Registration_Semiautomatic_Homework.ipynb b/Python/67_Registration_Semiautomatic_Homework.ipynb
index d15e5f5a..012ef38e 100644
--- a/Python/67_Registration_Semiautomatic_Homework.ipynb
+++ b/Python/67_Registration_Semiautomatic_Homework.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/68_Registration_Errors.ipynb b/Python/68_Registration_Errors.ipynb
index 971173b8..161d7d92 100644
--- a/Python/68_Registration_Errors.ipynb
+++ b/Python/68_Registration_Errors.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/69_x-ray-panorama.ipynb b/Python/69_x-ray-panorama.ipynb
index 25b01e26..2ed024b6 100755
--- a/Python/69_x-ray-panorama.ipynb
+++ b/Python/69_x-ray-panorama.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {
diff --git a/Python/70_Data_Augmentation.ipynb b/Python/70_Data_Augmentation.ipynb
index 43e982d2..6cfcc93d 100755
--- a/Python/70_Data_Augmentation.ipynb
+++ b/Python/70_Data_Augmentation.ipynb
@@ -23,12 +23,19 @@
    "outputs": [],
    "source": [
     "# Setup to enable running the notebook in the Google Colab environment\n",
-    "import os\n",
     "\n",
-    "if \"COLAB_NOTEBOOK_ID\" in os.environ:\n",
-    "    !git clone https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
-    "    %cd SimpleITK-Notebooks/Python\n",
-    "    !pip install -q -r requirements.txt"
+    "try:\n",
+    "    import google.colab\n",
+    "    import pathlib\n",
+    "\n",
+    "    repo_dir = pathlib.Path(\"/content/SimpleITK-Notebooks\")\n",
+    "    if not repo_dir.exists():\n",
+    "        !git clone --depth 1 https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks\n",
+    "    %cd /content/SimpleITK-Notebooks/Python\n",
+    "    !pip install -q -r requirements.txt\n",
+    "\n",
+    "except ImportError:\n",
+    "    pass  # not on Colab"
    ]
   },
   {