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 _get_markup_for_tags(self, tag_names):
        """Given a list of tags names, generates the pango markup to render
         that list with the tag colors used in GTG

        @param tag_names: the list of the tags (strings)
        @return str: the pango markup string
        """
        if ALLTASKS_TAG in tag_names:
            tags_txt = ""
        else:
            tags_txt = get_colored_tags_markup(self.req, tag_names)
        return "<small>" + tags_txt + "</small>"