Remove import fallbacks.

examples/test_examples.py

@@ -18,19 +18,13 @@ import argparse
 import logging
 import sys
 import unittest
+from unittest.mock import patch
 
 import run_generation
 import run_glue
 import run_squad
 
 
-try:
-    # python 3.4+ can use builtin unittest.mock instead of mock package
-    from unittest.mock import patch
-except ImportError:
-    from mock import patch
-
-
 logging.basicConfig(level=logging.DEBUG)
 
 logger = logging.getLogger()

src/transformers/file_utils.py

@@ -15,6 +15,7 @@ from contextlib import contextmanager
 from functools import partial, wraps
 from hashlib import sha256
 from io import open
+from urllib.parse import urlparse
 
 import boto3
 import requests
@@ -65,10 +66,6 @@ except ImportError:
     )
 default_cache_path = os.path.join(torch_cache_home, "transformers")
 
-try:
-    from urllib.parse import urlparse
-except ImportError:
-    from urlparse import urlparse
 
 try:
     from pathlib import Path

src/transformers/tokenization_gpt2.py

@@ -18,6 +18,7 @@
 import json
 import logging
 import os
+from functools import lru_cache
 from io import open
 
 import regex as re
@@ -25,15 +26,6 @@ import regex as re
 from .tokenization_utils import PreTrainedTokenizer
 
 
-try:
-    from functools import lru_cache
-except ImportError:
-    # Just a dummy decorator to get the checks to run on python2
-    # because honestly I don't want to support a byte-level unicode BPE tokenizer on python 2 right now.
-    def lru_cache():
-        return lambda func: func
-
-
 logger = logging.getLogger(__name__)
 
 VOCAB_FILES_NAMES = {

src/transformers/tokenization_roberta.py

@@ -20,15 +20,6 @@ import logging
 from .tokenization_gpt2 import GPT2Tokenizer
 
 
-try:
-    from functools import lru_cache
-except ImportError:
-    # Just a dummy decorator to get the checks to run on python2
-    # because honestly I don't want to support a byte-level unicode BPE tokenizer on python 2 right now.
-    def lru_cache():
-        return lambda func: func
-
-
 logger = logging.getLogger(__name__)
 
 VOCAB_FILES_NAMES = {