with an existing directory or empty string raises :exc:`ImportError`.
Otherwise, a :class:`NullImporter` instance is returned.
- Python adds instances of this type to ``sys.path_importer_cache`` for any path
- entries that are not directories and are not handled by any other path hooks on
- ``sys.path_hooks``. Instances have only one method:
-
+ Instances have only one method:
.. method:: NullImporter.find_module(fullname [, path])
This method always returns ``None``, indicating that the requested module could
not be found.
+ .. versionchanged:: 3.3
+ ``None`` is inserted into ``sys.path_importer_cache`` instead of an
+ instance of :class:`NullImporter`.
+
.. _examples-imp:
A dictionary acting as a cache for :term:`finder` objects. The keys are
paths that have been passed to :data:`sys.path_hooks` and the values are
the finders that are found. If a path is a valid file system path but no
- explicit finder is found on :data:`sys.path_hooks` then ``None`` is
- stored to represent the implicit default finder should be used. If the path
- is not an existing path then :class:`imp.NullImporter` is set.
+ finder is found on :data:`sys.path_hooks` then ``None`` is
+ stored.
Originally specified in :pep:`302`.
+ .. versionchanged:: 3.3
+ ``None`` is stored instead of :class:`imp.NullImporter` when no finder
+ is found.
+
.. data:: platform