Add support for multiple models for one config in auto classes (#11150)

* Add support for multiple models for one config in auto classes

* Use get_values everywhere

* Prettier doc

tests/test_modeling_convbert.py

@@ -19,6 +19,7 @@ import unittest
 
 from tests.test_modeling_common import floats_tensor
 from transformers import is_torch_available
+from transformers.models.auto import get_values
 from transformers.testing_utils import require_torch, slow, torch_device
 
 from .test_configuration_common import ConfigTester
@@ -352,7 +353,7 @@ class ConvBertModelTest(ModelTesterMixin, unittest.TestCase):
                 if "labels" in inputs_dict:
                     correct_outlen += 1  # loss is added to beginning
                 # Question Answering model returns start_logits and end_logits
-                if model_class in MODEL_FOR_QUESTION_ANSWERING_MAPPING.values():
+                if model_class in get_values(MODEL_FOR_QUESTION_ANSWERING_MAPPING):
                     correct_outlen += 1  # start_logits and end_logits instead of only 1 output
                 if "past_key_values" in outputs:
                     correct_outlen += 1  # past_key_values have been returned