6.1.3 - check that initial_value is explicitly None
IntCharacteristic, FloatCharacteristic, and StructCharacteristic were not checking that initial_value was explicitly None, but just that it was false. This made it not possible to give an initial value of 0, 0.0, or b'', respectively.
To use in CircuitPython, simply install the Adafruit CircuitPython bundle.
To use in CPython, pip3 install adafruit-circuitpython-ble.
Read the docs for info on how to use it.