Overriding __getattr__ for the sake of API Design

getattr_example.py

class Color:
    def __init__(self):
        pass

    def __getattr__(self, name):
        if name is 'saturation':
            # Warn user of hls / saturation
            saturation_warning = 'Color.saturation is ambiguous. Use Color.hls_saturation or Color.hsv_saturation'
            raise AttributeError(saturation_warning)
        else:
            # Default
            raise AttributeError


In action:

>>> c = Color()
>>> c.saturation
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "test.py", line 9, in __getattr__
    raise AttributeError(saturation_warning)
AttributeError: Color.saturation is ambiguous.Use Color.hls_saturation or Color.hsv_saturation

Source:
http://stackoverflow.com/questions/2405590/how-do-i-override-getattr-in-python-without-breaking-the-default-behavior