def load(self, requirements_file=None):
        """Load or reload requirements from a requirements.txt file.

        :param requirements_file: if not given, the filename used from
            initialization will be read again.
        """
        if requirements_file is None:
            requirements_file = self.filename
            if requirements_file is None:
                raise ValueError("no filename provided")
        elif isinstance(requirements_file, text_type):
            requirements_file = Path(requirements_file)
        self.clear()
        with requirements_file.open() as f:
            self.loads(f.read())

        if isinstance(requirements_file, (text_type, Path)):
            self.filename = requirements_file
def __init__(self, reddit, term, config, oauth, url=None, submission=None):
        super(SubmissionPage, self).__init__(reddit, term, config, oauth)

        self.controller = SubmissionController(self, keymap=config.keymap)

        if url:
            self.content = SubmissionContent.from_url(
                reddit, url, term.loader,
                max_comment_cols=config['max_comment_cols'])
        else:
            self.content = SubmissionContent(
                submission, term.loader,
                max_comment_cols=config['max_comment_cols'])
        # Start at the submission post, which is indexed as -1
        self.nav = Navigator(self.content.get, page_index=-1)
        self.selected_subreddit = None