code: def test_attributes(self):
      for feature in features:
          value = getattr(__future__, feature)
  
          optional = value.getOptionalRelease()
          mandatory = value.getMandatoryRelease()
  
          a = self.assertTrue
          e = self.assertEqual
  
          def check(t, name):
              a(isinstance(t, tuple), "%s isn't tuple" % name)
              e(len(t), 5, "%s isn't 5-tuple" % name)
              (major, minor, micro, level, serial) = t
              a(isinstance(major, int), "%s major isn't int" % name)
              a(isinstance(minor, int), "%s minor isn't int" % name)
              a(isinstance(micro, int), "%s micro isn't int" % name)
              a(isinstance(level, str), "%s level isn't string" % name)
              a(
                  level in GOOD_SERIALS,
                  "%s level string has unknown value" % name,
              )
              a(isinstance(serial, int), "%s serial isn't int" % name)
  
          check(optional, "optional")
          if mandatory is not None:
              check(mandatory, "mandatory")
              a(
                  optional < mandatory,
                  "optional not less than mandatory, and mandatory not None",
              )
  
          a(
              hasattr(value, "compiler_flag"),
              "feature is missing a .compiler_flag attr",
          )
          # Make sure the compile accepts the flag.
          compile("", "<test>", "exec", value.compiler_flag)
          a(
              isinstance(getattr(value, "compiler_flag"), int),
              ".compiler_flag isn't int",
          )
  
imports: import unittest
  import __future__
label_desc: Use image node_id 2 for calling the FutureTest obj's underlying member method code with example usage: obj.test_attributes() without return types