chore: import upstream snapshot with attribution

nemo/core/classes/__init__.py

@@ -0,0 +1,35 @@
+# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import hydra
+import lightning.pytorch
+import omegaconf
+
+from nemo.core.classes.common import (
+    FileIO,
+    Model,
+    PretrainedModelInfo,
+    Serialization,
+    Typing,
+    is_typecheck_enabled,
+    typecheck,
+)
+from nemo.core.classes.dataset import Dataset, IterableDataset
+from nemo.core.classes.exportable import Exportable, ExportFormat
+from nemo.core.classes.loss import Loss
+from nemo.core.classes.mixins import access_mixins, adapter_mixins, hf_io_mixin
+from nemo.core.classes.modelPT import ModelPT
+from nemo.core.classes.module import NeuralModule
+from nemo.utils import exceptions