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 test_reserve_unreserve_volume(self):
        """Test reserving and unreserving volume"""
        # Mark volume as reserved.
        self.volumes_client.reserve_volume(self.volume['id'])
        # To get the volume info
        body = self.volumes_client.show_volume(self.volume['id'])['volume']
        self.assertIn('attaching', body['status'])
        # Unmark volume as reserved.
        self.volumes_client.unreserve_volume(self.volume['id'])
        # To get the volume info
        body = self.volumes_client.show_volume(self.volume['id'])['volume']
        self.assertIn('available', body['status'])