dht22 calculates temperature incorrectly at negative values

[m32]

I recently installed DHT22, and to my surprise, after a few days of frost, it showed a temperature of -3274.5.
The calculations performed by dht.py are consistent with the documentation, but they are incorrect.

Example and proposal for new calculation:

class DHTBase:
    def xbuf(self, buf):
        self.buf = buf

class DHT22(DHTBase):
    def humidity(self):
        return (self.buf[0] << 8 | self.buf[1]) * 0.1

    def temperature(self):
        t = (self.buf[2] & 0x7f) << 8 | self.buf[3]
        if self.buf[2] & 0x80:
            t = - t ^ 0x7fff
        return t*0.1

def main():
    # hum = 69, temp=-3274.5 = -2.2
    cls = DHT22()
    cls.xbuf([2, 183, 255, 233, 162])
    temp = cls.temperature()
    hum = cls.humidity()
    print(f'temp={temp:.1f} hum={hum:.1f}')

main()