def remove(self, elem):
        """Remove a requirement.

        :param elem: a string or :class:`Requirement` instance.
        """
        if isinstance(elem, text_type):
            for requirement in self:
                if requirement.package == elem:
                    return super(Requirements, self).remove(requirement)
        return super(Requirements, self).remove(elem)
def _load_data(self, directory):
        try:
            with open(directory, 'r') as f:
                data = f.read()
                return literal_eval(data)
        except OSError as e:
            raise