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 update_submodules(cls, location):
        if not os.path.exists(os.path.join(location, '.gitmodules')):
            return
        cls.run_command(
            ['submodule', 'update', '--init', '--recursive', '-q'],
            cwd=location,
        )