chore: import upstream snapshot with attribution

decoding/GAD/fairseq/data/legacy/__init__.py

@@ -0,0 +1,16 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from .block_pair_dataset import BlockPairDataset
+from .masked_lm_dataset import MaskedLMDataset
+from .masked_lm_dictionary import BertDictionary, MaskedLMDictionary
+
+
+__all__ = [
+    "BertDictionary",
+    "BlockPairDataset",
+    "MaskedLMDataset",
+    "MaskedLMDictionary",
+]