Run a method and return the content Record from the returned XML.

        A method is a relative path from an Entity that is not itself
        an Entity. _run_action assumes that the returned XML is an
        Atom field containing one Entry, and the contents of Entry is
        what should be the return value. This is right in enough cases
        to make this method useful.

def _run_action(self, path_segment, **kwargs):
        """Run a method and return the content Record from the returned XML.

        A method is a relative path from an Entity that is not itself
        an Entity. _run_action assumes that the returned XML is an
        Atom field containing one Entry, and the contents of Entry is
        what should be the return value. This is right in enough cases
        to make this method useful.
        """
        response = self.get(path_segment, **kwargs)
        data = self._load_atom_entry(response)
        rec = _parse_atom_entry(data)
        return rec.content