code: def parse_buffer(buffer, mode="exec", flags=[], version=None, engine=None):
      
  
      if version is None:
          version = sys.version_info[0:2]
  
      if engine is None:
          engine = pythonparser_diagnostic.Engine()
  
      lexer = pythonparser_lexer.Lexer(buffer, version, engine)
      if mode in ("single", "eval"):
          lexer.interactive = True
  
      parser = pythonparser_parser.Parser(lexer, version, engine)
      parser.add_flags(flags)
  
      if mode == "exec":
          return parser.file_input(), lexer.comments
      elif mode == "single":
          return parser.single_input(), lexer.comments
      elif mode == "eval":
          return parser.eval_input(), lexer.comments
docs: Like :meth:`parse`, but accepts a :class:`source.Buffer` instead of
      source and filename, and returns comments as well.
  
      :see: :meth:`parse`
      :return: (:class:`ast.AST`, list of :class:`source.Comment`)
          Abstract syntax tree and comments