docstr: Regression test for bpo-30570.
docstr_tok: ["Regression","test","for","bpo-30570","."]
code: def test_infinite_recursion_via_bases_tuple(self):
      """Regression test for bpo-30570."""
  
      class Failure(object):
          def __getattr__(self, attr):
              return (self, None)
  
      with support.infinite_recursion():
          with self.assertRaises(RecursionError):
              issubclass(Failure(), int)
  
imports: import unittest
  import typing
  from test import support
label_desc: Use image node_id 12 for calling the TestIsInstanceIsSubclass obj's underlying member method code with example usage: obj.test_infinite_recursion_via_bases_tuple() and returns: self,  None