Create an instance of Lark with the grammar given by its filename

        If rel_to is provided, the function will find the grammar filename in relation to it.

        Example:

            >>> Lark.open("grammar_file.lark", rel_to=__file__, parser="lalr")
            Lark(...)

def open(cls, grammar_filename, rel_to=None, **options):
        """Create an instance of Lark with the grammar given by its filename

        If rel_to is provided, the function will find the grammar filename in relation to it.

        Example:

            >>> Lark.open("grammar_file.lark", rel_to=__file__, parser="lalr")
            Lark(...)

        """
        if rel_to:
            basepath = os.path.dirname(rel_to)
            grammar_filename = os.path.join(basepath, grammar_filename)
        with open(grammar_filename, encoding='utf8') as f:
            return cls(f, **options)