code: def parse_executable_definition(lexer: Lexer) -> ExecutableDefinitionNode:
      
      if peek(lexer, TokenKind.NAME):
          func = _parse_executable_definition_functions.get(cast(str, lexer.token.value))
          if func:
              return func(lexer)
      elif peek(lexer, TokenKind.BRACE_L):
          return parse_operation_definition(lexer)
      raise unexpected(lexer)
docs: ExecutableDefinition: OperationDefinition or FragmentDefinition