Fix F401 flake8 warning (x152 / 268).

This change is mostly autogenerated with:

    $ python -m autoflake --in-place --recursive examples templates transformers utils hubconf.py setup.py

I made minor changes in the generated diff.

examples/contrib/run_camembert.py

-import tarfile
-import urllib.request
-from pathlib import Path
-
 import torch
 
 from transformers.modeling_camembert import CamembertForMaskedLM

examples/run_bertology.py

@@ -22,7 +22,7 @@
 import argparse
 import logging
 import os
-from datetime import datetime, timedelta
+from datetime import datetime
 
 import numpy as np
 import torch

examples/summarization/configuration_bertabs.py

@@ -14,9 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """ BertAbs configuration """
-import json
 import logging
-import sys
 
 from transformers import PretrainedConfig
 

templates/adding_a_new_model/configuration_xxx.py

@@ -16,10 +16,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 import six
 

templates/adding_a_new_model/modeling_tf_xxx.py

@@ -21,14 +21,8 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import copy
 import itertools
-import json
 import logging
-import math
-import os
-import sys
-from io import open
 
 import numpy as np
 import tensorflow as tf

templates/adding_a_new_model/modeling_xxx.py

@@ -20,14 +20,9 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import copy
 import itertools
-import json
 import logging
-import math
 import os
-import sys
-from io import open
 
 import torch
 from torch import nn

templates/adding_a_new_model/tests/modeling_tf_xxx_test.py

@@ -14,7 +14,6 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
-import sys
 import unittest
 
 from transformers import XxxConfig, is_tf_available

transformers/configuration_bert.py

@@ -17,10 +17,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/configuration_ctrl.py

@@ -16,10 +16,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/configuration_distilbert.py

@@ -15,10 +15,7 @@
 """ DistilBERT model configuration """
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/configuration_gpt2.py

@@ -17,10 +17,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/configuration_openai.py

@@ -17,10 +17,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/configuration_t5.py

@@ -16,10 +16,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 import six
 

transformers/configuration_transfo_xl.py

@@ -17,10 +17,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/configuration_xlm.py

@@ -15,10 +15,7 @@
 """ XLM configuration """
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/configuration_xlnet.py

@@ -16,10 +16,7 @@
 """ XLNet configuration """
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import json
 import logging
-import sys
-from io import open
 
 from .configuration_utils import PretrainedConfig
 

transformers/data/metrics/__init__.py

@@ -14,9 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import csv
 import logging
-import sys
 
 
 logger = logging.getLogger(__name__)

transformers/data/processors/squad.py

-import collections
 import json
 import logging
 import os

transformers/modeling_ctrl.py

@@ -17,13 +17,7 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-import collections
-import json
 import logging
-import math
-import os
-import sys
-from io import open
 
 import numpy as np
 import torch

transformers/modeling_distilbert.py

@@ -20,11 +20,8 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 
 import copy
 import itertools
-import json
 import logging
 import math
-import sys
-from io import open
 
 import numpy as np
 import torch