How to use the pypyr.cache.parsercache.contextparser_cache.get_context_parser function in pypyr

context_in_args: list of string. Input arguments from console.

    Returns:
        pypyr.context.Context() instance.

    Raises:
        AttributeError: parser specified on pipeline missing get_parsed_context
                        function.

    """
    logger.debug("starting")

    if 'context_parser' in pipeline:
        parser_module_name = pipeline['context_parser']
        logger.debug("context parser specified: %s", parser_module_name)
        get_parsed_context = contextparser_cache.get_context_parser(
            parser_module_name)

        logger.debug("running parser %s", parser_module_name)
        result_context = get_parsed_context(context_in_args)
        logger.debug("context parse %s done", parser_module_name)
        # Downstream steps likely to expect context not to be None, hence
        # empty rather than None.
        if result_context is None:
            logger.debug(
                "%s returned None. Using empty context instead",
                parser_module_name
            )
            return pypyr.context.Context()
        else:
            return pypyr.context.Context(result_context)
    else: