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authorGuido van Rossum <guido@python.org>2016-09-11 01:49:14 (GMT)
committerGuido van Rossum <guido@python.org>2016-09-11 01:49:14 (GMT)
commit1816dfe65f5cba50331342d153e99482b18b2d4e (patch)
treed7f58dd05229756a6015fd05932d7fc9e63e6a94
parentcc66a6528d0f756a23da29e31b2e6332def03a18 (diff)
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Issue #28073: Improve wording around None. Michael Lee.
-rw-r--r--Doc/library/typing.rst6
1 files changed, 4 insertions, 2 deletions
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index 83a8dcf..640255a 100644
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -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