DOC: Add a note to provide clarification about `__all__: List[str]`

Addresses https://github.com/numpy/numpy/pull/17844#discussion_r530495392

1 files changed, 3 insertions, 0 deletions

diff --git a/numpy/typing/__init__.py b/numpy/typing/__init__.py
index 054777c1a..e72e8fb4d 100644
--- a/numpy/typing/__init__.py
+++ b/numpy/typing/__init__.py
@@ -137,6 +137,9 @@ else:
     # Ensure that all objects within this module are accessible while
     # static type checking. This includes private ones, as we need them
     # for internal use.
+    #
+    # Declare to mypy that `__all__` is a list of strings without assigning
+    # an explicit value
     __all__: List[str]