def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def prompt_subreddit(self):
        "Open a prompt to navigate to a different subreddit"

        name = self.term.prompt_input('Enter page: /')
        if name is not None:
            with self.term.loader('Loading page'):
                content = SubredditContent.from_name(
                    self.reddit, name, self.term.loader)
            if not self.term.loader.exception:
                self.selected_subreddit = content
                self.active = False