code: def builtin_folding(value):
      
      if isinstance(value, (type(None), bool)):
          name = str(value)
      elif value.__name__ in ("bool", "float", "int"):
          name = value.__name__ + "_"
      else:
          name = value.__name__
      return ast.Attribute(ast.Name('__builtin__', ast.Load(), None),
                           name, ast.Load())
docs: Convert builtin function to ast expression.