async w/ python 3.8 compatibility sans warnings

.travis.yml

@@ -1,10 +1,10 @@
 language: python
 python:
   - "2.7"
-  - "3.3"
-  - "3.4"
   - "3.5"
   - "3.6"
+  - "3.7"
+  - "3.8"
 install: # No dependencies
 script:
   - pip install -U pip setuptools

ratelimiter/__init__.py

@@ -17,7 +17,7 @@
 import sys
 
 __author__ = 'Frazer McLean <frazer@frazermclean.co.uk>'
-__version__ = '1.2.0.post0'
+__version__ = '1.2.0.post1'
 __license__ = 'Apache'
 __description__ = 'Simple python rate limiting object'
 

ratelimiter/_async.py

@@ -19,7 +19,7 @@ async def __aenter__(self):
         if self._alock is None:
             self._init_async_lock()
 
-        with await self._alock:
+        async with self._alock:
             # We want to ensure that no more than max_calls were run in the allowed
             # period. For this, we store the last timestamps of each call and run
             # the rate verification upon each __enter__ call.
@@ -32,4 +32,5 @@ async def __aenter__(self):
                     await asyncio.sleep(sleeptime)
             return self
 
-    __aexit__ = asyncio.coroutine(RateLimiter.__exit__)
+    async def __aexit__(self, exc_type, exc_value, traceback):
+         return super(AsyncRateLimiter, self).__exit__(exc_type, exc_value, traceback)