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 __init__(self, m1, m2):
        super(differencematcher, self).__init__(m1._root, m1._cwd)
        self._m1 = m1
        self._m2 = m2
        self.bad = m1.bad
        self.traversedir = m1.traversedir