Open an instance of the submission page for the given submission URL.

def open_submission_page(self, url=None, submission=None):
        """
        Open an instance of the submission page for the given submission URL.
        """
        from .submission_page import SubmissionPage

        with self.term.loader('Loading submission'):
            page = SubmissionPage(self.reddit, self.term, self.config,
                                  self.oauth, url=url, submission=submission)
        if not self.term.loader.exception:
            return page