'This is a "constructor" for the FormID class.
Users configure form-ids as JSON objects in the configuration, we need to
parse this here to convert them to FormIDs
:param json_string: A user provided string which should be in json format
:return: A FormIDMatcher object'

@classmethod
def from_json(cls, json_string):

    json_data = json.loads(json_string)
    return cls.from_json_list_data(json_data)
