Changed summary line of docstring to follow PEP 0257 - update

Quoting https://www.python.org/dev/peps/pep-0257/#one-line-docstrings

"The docstring is a phrase ending in a period. It prescribes the function or method's effect as a command ("Do this", "Return that"), not as a description; e.g. don't write "Returns the pathname ...".