Create an external feed.

        Create a new external feed for the course or group.

def create_external_feed_courses(self, url, course_id, header_match=None, verbosity=None):
        """
        Create an external feed.

        Create a new external feed for the course or group.
        """
        path = {}
        data = {}
        params = {}

        # REQUIRED - PATH - course_id
        """ID"""
        path["course_id"] = course_id

        # REQUIRED - url
        """The url to the external rss or atom feed"""
        data["url"] = url

        # OPTIONAL - header_match
        """If given, only feed entries that contain this string in their title will be imported"""
        if header_match is not None:
            data["header_match"] = header_match

        # OPTIONAL - verbosity
        """Defaults to "full""""
        if verbosity is not None:
            self._validate_enum(verbosity, ["full", "truncate", "link_only"])
            data["verbosity"] = verbosity

        self.logger.debug("POST /api/v1/courses/{course_id}/external_feeds with query params: {params} and form data: {data}".format(params=params, data=data, **path))
        return self.generic_request("POST", "/api/v1/courses/{course_id}/external_feeds".format(**path), data=data, params=params, single_item=True)