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 deserialize(self, value):
        value = decode(value)
        if "\n" in value:
            values = re.split(r"\s*\n\s*", value)
        else:
            values = re.split(r"\s*,\s*", value)
        values = tuple(v.strip() for v in values if v.strip())
        validators.validate_required(values, self._required)
        return tuple(values)