For consistency, you should always format docstrings like this:

    """
    Docstring.
    """

Note the double-quotes (not single-quotes), newlines, and period.  Please change all the docstrings in this file to match this format.
(There codebase is currently inconsistent about this, but we're trying to adopt this for all new code)

In addition, you should write a comment explaining the type of each argument and return value.  For example:

    def parse_json(response):
        """
        Parse `response` (an HTTP response object) and return the JSON-decoded string (a `str`).
        """