asyncio: pyflakes, remove unused import

tests: Remove unused function; inline another function

Lib/asyncio/base_events.py

@@ -636,7 +636,7 @@ class BaseEventLoop(events.AbstractEventLoop):
 
         try:
             yield from waiter
-        except Exception as exc:
+        except Exception:
             transport.close()
             raise
 

Lib/asyncio/selector_events.py

@@ -10,7 +10,6 @@ import collections
 import errno
 import functools
 import socket
-import sys
 try:
     import ssl
 except ImportError:  # pragma: no cover

Lib/test/test_asyncio/test_streams.py

@@ -415,10 +415,6 @@ class StreamReaderTests(test_utils.TestCase):
         def set_err():
             stream.set_exception(ValueError())
 
-        @asyncio.coroutine
-        def readline():
-            yield from stream.readline()
-
         t1 = asyncio.Task(stream.readline(), loop=self.loop)
         t2 = asyncio.Task(set_err(), loop=self.loop)
 
@@ -429,11 +425,7 @@ class StreamReaderTests(test_utils.TestCase):
     def test_exception_cancel(self):
         stream = asyncio.StreamReader(loop=self.loop)
 
-        @asyncio.coroutine
-        def read_a_line():
-            yield from stream.readline()
-
-        t = asyncio.Task(read_a_line(), loop=self.loop)
+        t = asyncio.Task(stream.readline(), loop=self.loop)
         test_utils.run_briefly(self.loop)
         t.cancel()
         test_utils.run_briefly(self.loop)