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Issue #28073: Improve wording around None. Michael Lee.

This commit is contained in:
Guido van Rossum 2016-09-10 18:49:14 -07:00
parent cc66a6528d
commit 1816dfe65f
1 changed files with 4 additions and 2 deletions
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Doc/library/typing.rst
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@ -59,6 +59,9 @@ Type aliases are useful for simplifying complex type signatures. For example::
servers: List[Tuple[Tuple[str, int], Dict[str, str]]]) -> None:
...
Note that ``None`` as a type hint is a special case and is replaced by
``type(None)``.
NewType
-------
@ -148,7 +151,6 @@ For example::
It is possible to declare the return type of a callable without specifying
the call signature by substituting a literal ellipsis
for the list of arguments in the type hint: ``Callable[..., ReturnType]``.
``None`` as a type hint is a special case and is replaced by ``type(None)``.
Generics
--------
@ -443,7 +445,7 @@ The module defines the following classes, functions and decorators:
Optional type.
``Optional[X]`` is equivalent to ``Union[X, type(None)]``.
``Optional[X]`` is equivalent to ``Union[X, None]``.
Note that this is not the same concept as an optional argument,
which is one that has a default. An optional argument with a