 The object's module is used:

    - As a default namespace, if `globs` is not specified.
    - To prevent the DocTestFinder from extracting DocTests
      from objects that are imported from other modules.
    - To find the name of the file containing the object.
    - To help find the line number of the object within its
      file.

Contained objects whose module does not match `module` are ignored.

If `module` is False, no attempt to find the module will be made.
This is obscure, of use mostly in tests:  if `module` is False, or
is None but cannot be found automatically, then all objects are
considered to belong to the (non-existent) module, so all contained
objects will (recursively) be searched for doctests.

The globals for each DocTest is formed by combining `globs`
and `extraglobs` (bindings in `extraglobs` override bindings
in `globs`).  A new copy of the globals dictionary is created
for each DocTest.  If `globs` is not specified, then it
defaults to the module's `__dict__`, if specified, or {}
otherwise.  If `extraglobs` is not specified, then it defaults
to {}.

Nr7