code: def open(cls, grammar_filename, rel_to=None, **options):
          
          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)
docs: 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(...)