Extract strings from the docstrings

        .. code-block:: text

            * synopsis: ``%shorten{text, max_size}``
            * example: ``%shorten{$title, 32}``
            * description: Shorten “text” on word boundarys.

def extract_value(self, string, key, inline_code=True):
        """Extract strings from the docstrings

        .. code-block:: text

            * synopsis: ``%shorten{text, max_size}``
            * example: ``%shorten{$title, 32}``
            * description: Shorten “text” on word boundarys.

        """
        regex = r'\* ' + key + ': '
        if inline_code:
            regex = regex + '``(.*)``'
        else:
            regex = regex + '(.*)'
        value = re.findall(regex, string)
        if value:
            return value[0].replace('``', '')
        else:
            return False