Import collection ABC's from correct module (#384)

* Move ABCs imports to compat.py to reuse the imports from other modules

* Import collection ABC's from correct module

jwt/api_jws.py

@@ -1,7 +1,6 @@
 import binascii
 import json
 import warnings
-from collections import Mapping
 try:
     # import required by mypy to perform type checking, not used for normal execution
     from typing import Callable, Dict, List, Optional, Union # NOQA
@@ -11,7 +10,7 @@
 from .algorithms import (
     Algorithm, get_default_algorithms, has_crypto, requires_cryptography  # NOQA
 )
-from .compat import binary_type, string_types, text_type
+from .compat import Mapping, binary_type, string_types, text_type
 from .exceptions import (
     DecodeError, InvalidAlgorithmError, InvalidSignatureError,
     InvalidTokenError

jwt/api_jwt.py

@@ -2,11 +2,6 @@
 import warnings
 from calendar import timegm
 from datetime import datetime, timedelta
-try:
-    # Importing ABCs from collections will be removed in PY3.8
-    from collections.abc import Iterable, Mapping
-except ImportError:
-    from collections import Iterable, Mapping
 try:
     # import required by mypy to perform type checking, not used for normal execution
     from typing import Callable, Dict, List, Optional, Union # NOQA
@@ -15,7 +10,7 @@
 
 from .api_jws import PyJWS
 from .algorithms import Algorithm, get_default_algorithms  # NOQA
-from .compat import string_types
+from .compat import Iterable, Mapping, string_types
 from .exceptions import (
     DecodeError, ExpiredSignatureError, ImmatureSignatureError,
     InvalidAudienceError, InvalidIssuedAtError,

jwt/compat.py

@@ -20,6 +20,11 @@
 
 string_types = (text_type, binary_type)
 
+try:
+    # Importing ABCs from collections will be removed in PY3.8
+    from collections.abc import Iterable, Mapping
+except ImportError:
+    from collections import Iterable, Mapping
 
 try:
     constant_time_compare = hmac.compare_digest