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2.5 Built-in Constants

A small number of constants live in the built-in namespace. They are:

False: The false value of the bool type. New in version 2.3.

True: The true value of the bool type. New in version 2.3.

None: The sole value of types.NoneType. None is frequently used to represent the absence of a value, as when default arguments are not passed to a function.

NotImplemented: Special value which can be returned by the ``rich comparison'' special methods (__eq__(), __lt__(), and friends), to indicate that the comparison is not implemented with respect to the other type.

Ellipsis: Special value used in conjunction with extended slicing syntax.

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