Ignore F401 flake8 warning (x326 / 594).

transformers/__init__.py

+# flake8: noqa
+# There's no way to ignore "F401 '...' imported but unused" warnings in this
+# module, but to preserve other warnings. So, don't check this module at all.
+
 __version__ = "2.3.0"
 
 # Work around to update TensorFlow's absl.logging threshold which alters the

transformers/data/__init__.py

+# flake8: noqa
+# There's no way to ignore "F401 '...' imported but unused" warnings in this
+# module, but to preserve other warnings. So, don't check this module at all.
+
 from .metrics import is_sklearn_available
 from .processors import (
     DataProcessor,

transformers/data/processors/__init__.py

+# flake8: noqa
+# There's no way to ignore "F401 '...' imported but unused" warnings in this
+# module, but to preserve other warnings. So, don't check this module at all.
+
 from .glue import glue_convert_examples_to_features, glue_output_modes, glue_processors, glue_tasks_num_labels
 from .squad import SquadExample, SquadFeatures, SquadV1Processor, SquadV2Processor, squad_convert_examples_to_features
 from .utils import DataProcessor, InputExample, InputFeatures, SingleSentenceClassificationProcessor