def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, version)
def refresh_content(self, order=None, name=None):
        "Re-download comments and reset the page index"

        order = order or self.content.order
        url = name or self.content.name

        with self.term.loader('Refreshing page'):
            self.content = SubmissionContent.from_url(
                self.reddit, url, self.term.loader, order=order,
                max_comment_cols=self.config['max_comment_cols'])
        if not self.term.loader.exception:
            self.nav = Navigator(self.content.get, page_index=-1)