code: def yield_expr__33(self, yield_loc, arg):
          
          if isinstance(arg, ast.YieldFrom):
              arg.yield_loc = yield_loc
              arg.loc = arg.loc.join(arg.yield_loc)
              return arg
          elif arg is not None:
              return ast.Yield(value=arg,
                               yield_loc=yield_loc, loc=yield_loc.join(arg.loc))
          else:
              return ast.Yield(value=None,
                               yield_loc=yield_loc, loc=yield_loc)
docs: (3.3-) yield_expr: 'yield' [yield_arg]