In addition, there are cases when you want tests to be part of a module but not part
of the help text, which requires that the tests not be included in the docstring.
Doctest looks for a module-level variable called ``__test__`` and uses it to locate other
-tests. If ``M.__test__`` exists and is truthy, it must be a dict, and each
+tests. If ``M.__test__`` exists, it must be a dict, and each
entry maps a (string) name to a function object, class object, or string.
Function and class object docstrings found from ``M.__test__`` are searched, and
strings are treated as if they were docstrings. In output, a key ``K`` in
(or module :mod:`__main__` if *m* is not supplied or is ``None``), starting with
``m.__doc__``.
- Also test examples reachable from dict ``m.__test__``, if it exists and is not
- ``None``. ``m.__test__`` maps names (strings) to functions, classes and
+ Also test examples reachable from dict ``m.__test__``, if it exists.
+ ``m.__test__`` maps names (strings) to functions, classes and
strings; function and class docstrings are searched for examples; strings are
searched directly, as if they were docstrings.