@@ -1,4 +1,3 @@
-.. Generated by synthtool. DO NOT EDIT!
 ############
 Contributing
 ############
@@ -22,7 +21,7 @@ In order to add a feature:
 documentation.
 
 - The feature must work fully on the following CPython versions:
-2.7, 3.6, 3.7, 3.8 and 3.9 on both UNIX and Windows.
+3.6, 3.7, 3.8 and 3.9 on both UNIX and Windows.
 
 - The feature must not add unnecessary dependencies (where
 "unnecessary" is of course subjective, but new dependencies should
@@ -77,8 +76,8 @@ We use `nox <https://nox.readthedocs.io/en/latest/>`__ to instrument our tests.
 
 .. note::
 
-The unit tests and system tests are described in the
-``noxfile.py`` files in each directory.
+The unit tests tests are described in the ``noxfile.py`` files
+in each directory.
 
 .. nox: https://pypi.org/project/nox/
 
@@ -133,29 +132,6 @@ Exceptions to PEP8:
 "Function-Under-Test"), which is PEP8-incompliant, but more readable.
 Some also use a local variable, ``MUT`` (short for "Module-Under-Test").
 
-********************
-Running System Tests
-********************
-
-- To run system tests, you can execute::
-
-# Run all system tests
-$ nox -s system
-
-# Run a single system test
-$ nox -s system-3.8 -- -k <name of test>
-
-
-.. note::
-
-System tests are only configured to run under Python 2.7 and 3.8.
-For expediency, we do not run them in older versions of Python 3.
-
-This alone will not run the tests. You'll need to change some local
-auth settings and change some configuration in your project to
-run all the tests.
-
-- System tests will be run against an actual project. You should use local credentials from gcloud when possible. See `Best practices for application authentication <https://cloud.google.com/docs/authentication/best-practices-applications#local_development_and_testing_with_the>`__. Some tests require a service account. For those tests see `Authenticating as a service account <https://cloud.google.com/docs/authentication/production>`__.
 
 *************
 Test Coverage
@@ -221,13 +197,11 @@ Supported Python Versions
 
 We support:
 
-- `Python 2.7`_
 - `Python 3.6`_
 - `Python 3.7`_
 - `Python 3.8`_
 - `Python 3.9`_
 
-.. _Python 2.7: https://docs.python.org/2.7/
 .. _Python 3.6: https://docs.python.org/3.6/
 .. _Python 3.7: https://docs.python.org/3.7/
 .. _Python 3.8: https://docs.python.org/3.8/
@@ -239,7 +213,7 @@ Supported versions can be found in our ``noxfile.py`` `config`_.
 .. _config: https://.com/googleapis/python-api-core/blob/master/noxfile.py
 
 
-We also explicitly decided to support Python 3 beginning with version 2.7.
+We also explicitly decided to support Python 3 beginning with version 3.6.
 Reasons for this include:
 
 - Encouraging use of newest versions of Python 3

@@ -1,7 +1,7 @@
 Core Library for Google Client Libraries
 ========================================
 
-|pypi| |versions|
+|pypi| |versions|
 
 This library is not meant to stand-alone. Instead it defines
 common helpers used by all Google API clients. For more information, see the
@@ -16,8 +16,13 @@ common helpers used by all Google API clients. For more information, see the
 
 Supported Python Versions
 -------------------------
-Python >= 3.5
+Python >= 3.6
 
-Deprecated Python Versions
---------------------------
-Python == 2.7. Python 2.7 support will be removed on January 1, 2020.
+
+Unsupported Python Versions
+---------------------------
+
+Python == 2.7, Python == 3.5.
+
+The last version of this library compatible with Python 2.7 and 3.5 is
+`google-api_core==1.31.1`.

@@ -103,25 +103,6 @@ After creation, you can pass it directly to a :class:`Client <google.cloud.clien
 
 .. _google-auth-guide: https://googleapis.dev/python/google-auth/latest/user-guide.html#service-account-private-key-files
 
-
-Google App Engine Standard First Generation Environment
--------------------------------------------------------
-
-These credentials are used only in the legacy Python 2.7
-`First Generation Standard Environment`_. All other App Engine
-runtimes use Compute Engine credentials.
-
-.. _First Generation Standard Environment: https://cloud.google.com/appengine/docs/standard/runtimes
-
-To create
-:class:`credentials <google.auth.app_engine.Credentials>`
-just for Google App Engine:
-
-.. code:: python
-
-from google.auth import app_engine
-credentials = app_engine.Credentials()
-
 Google Compute Engine Environment
 ---------------------------------
 

@@ -17,11 +17,10 @@
 import collections
 import datetime
 import logging
+import queue as queue_module
 import threading
 import time
 
-from six.moves import queue
-
 from google.api_core import exceptions
 
 _LOGGER = logging.getLogger(__name__)
@@ -71,7 +70,7 @@ class _RequestQueueGenerator(object):
 CPU consumed by spinning is pretty minuscule.
 
 Args:
-queue (queue.Queue): The request queue.
+queue (queue_module.Queue): The request queue.
 period (float): The number of seconds to wait for items from the queue
 before checking if the RPC is cancelled. In practice, this
 determines the maximum amount of time the request consumption
@@ -108,7 +107,7 @@ def __iter__(self):
 while True:
 try:
 item = self._queue.get(timeout=self._period)
-except queue.Empty:
+except queue_module.Empty:
 if not self._is_active():
 _LOGGER.debug(
 "Empty queue and inactive call, exiting request " "generator."
@@ -247,7 +246,7 @@ def __init__(self, start_rpc, initial_request=None, metadata=None):
 self._start_rpc = start_rpc
 self._initial_request = initial_request
 self._rpc_metadata = metadata
-self._request_queue = queue.Queue()
+self._request_queue = queue_module.Queue()
 self._request_generator = None
 self._is_active = False
 self._callbacks = []
@@ -645,6 +644,7 @@ def _thread_main(self, ready):
 # Keeping the lock throughout avoids that.
 # In the future, we could use `Condition.wait_for` if we drop
 # Python 2.7.
+# See: https://.com/googleapis/python-api-core/issues/211
 with self._wake:
 while self._paused:
 _LOGGER.debug("paused, waiting for waking.")

@@ -42,7 +42,7 @@ class ClientInfo(object):
 
 Args:
 python_version (str): The Python interpreter version, for example,
-``'2.7.13'``.
+``'3.9.6'``.
 grpc_version (Optional[str]): The gRPC library version.
 api_core_version (str): The google-api-core library version.
 gapic_version (Optional[str]): The sversion of gapic-generated client

@@ -101,7 +101,7 @@ def from_dict(options):
 """Construct a client options object from a mapping object.
 
 Args:
-options (six.moves.collections_abc.Mapping): A mapping object with client options.
+options (collections.abc.Mapping): A mapping object with client options.
 See the docstring for ClientOptions for details on valid arguments.
 """
 

@@ -18,12 +18,10 @@
 import datetime
 import re
 
-import pytz
-
 from google.protobuf import timestamp_pb2
 
 
-_UTC_EPOCH = datetime.datetime.utcfromtimestamp(0).replace(tzinfo=pytz.utc)
+_UTC_EPOCH = datetime.datetime(1970, 1, 1, tzinfo=datetime.timezone.utc)
 _RFC3339_MICROS = "%Y-%m-%dT%H:%M:%S.%fZ"
 _RFC3339_NO_FRACTION = "%Y-%m-%dT%H:%M:%S"
 # datetime.strptime cannot handle nanosecond precision: parse w/ regex
@@ -83,9 +81,9 @@ def to_microseconds(value):
 int: Microseconds since the unix epoch.
 """
 if not value.tzinfo:
-value = value.replace(tzinfo=pytz.utc)
+value = value.replace(tzinfo=datetime.timezone.utc)
 # Regardless of what timezone is on the value, convert it to UTC.
-value = value.astimezone(pytz.utc)
+value = value.astimezone(datetime.timezone.utc)
 # Convert the datetime to a microsecond timestamp.
 return int(calendar.timegm(value.timetuple()) * 1e6) + value.microsecond
 
@@ -156,7 +154,7 @@ def from_rfc3339(value):
 nanos = int(fraction) * (10 ** scale)
 micros = nanos // 1000
 
-return bare_seconds.replace(microsecond=micros, tzinfo=pytz.utc)
+return bare_seconds.replace(microsecond=micros, tzinfo=datetime.timezone.utc)
 
 
 from_rfc3339_nanos = from_rfc3339 # from_rfc3339_nanos method was deprecated.
@@ -256,7 +254,7 @@ def from_rfc3339(cls, stamp):
 bare.minute,
 bare.second,
 nanosecond=nanos,
-tzinfo=pytz.UTC,
+tzinfo=datetime.timezone.utc,
 )
 
 def timestamp_pb(self):
@@ -265,7 +263,11 @@ def timestamp_pb(self):
 Returns:
 (:class:`~google.protobuf.timestamp_pb2.Timestamp`): Timestamp message
 """
-inst = self if self.tzinfo is not None else self.replace(tzinfo=pytz.UTC)
+inst = (
+self
+if self.tzinfo is not None
+else self.replace(tzinfo=datetime.timezone.utc)
+)
 delta = inst - _UTC_EPOCH
 seconds = int(delta.total_seconds())
 nanos = self._nanosecond or self.microsecond * 1000
@@ -292,5 +294,5 @@ def from_timestamp_pb(cls, stamp):
 bare.minute,
 bare.second,
 nanosecond=stamp.nanos,
-tzinfo=pytz.UTC,
+tzinfo=datetime.timezone.utc,
 )