2.5 Built-in Constants
A small number of constants live in the built-in namespace. They are:
- The false value of the bool type. New in version 2.3.
- The true value of the bool type. New in version 2.3.
-
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.
- 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.
- Special value used in conjunction with extended slicing syntax.
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