Add assertion

Author: sergey-miryanov

Objects/exceptions.c

@@ -1091,6 +1091,7 @@ BaseExceptionGroup_repr(PyObject *op)
          * value of self.args[1]; but this can be mutable and go out-of-sync
          * with self.exceptions. Instead, use self.exceptions for accuracy,
          * making it look like self.args[1] for backwards compatibility. */
+        assert(PyTuple_Check(self->args));
         if (PyTuple_GET_SIZE(self->args) == 2 && PyList_Check(PyTuple_GET_ITEM(self->args, 1))) {
             PyObject *exceptions_list = PySequence_List(self->excs);
             if (!exceptions_list) {