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):
                self.stride = (4, 8, 16, 32, 64)
                self.short = (200, 100, 50, 25, 13)
                self.long = (334, 167, 84, 42, 21)