diff --git a/aioredis/abc.py b/aioredis/abc.py
index 0af13c65c..0c12783ae 100644
--- a/aioredis/abc.py
+++ b/aioredis/abc.py
@@ -5,8 +5,6 @@
 import abc
 import asyncio
 
-from abc import ABC
-
 
 __all__ = [
     'AbcConnection',
@@ -15,7 +13,7 @@
 ]
 
 
-class AbcConnection(ABC):
+class AbcConnection(abc.ABC):
     """Abstract connection interface."""
 
     @abc.abstractmethod
@@ -84,7 +82,7 @@ class AbcPool(AbcConnection):
     """
 
     @abc.abstractmethod
-    def get_connection(self):   # TODO: arguments
+    def get_connection(self, command, args=()):
         """
         Gets free connection from pool in a sync way.
 
@@ -109,7 +107,7 @@ def address(self):
         """Connection address or None."""
 
 
-class AbcChannel(ABC):
+class AbcChannel(abc.ABC):
     """Abstract Pub/Sub Channel interface."""
 
     @property
diff --git a/aioredis/locks.py b/aioredis/locks.py
index 7a73e61d2..f8b93c3ce 100644
--- a/aioredis/locks.py
+++ b/aioredis/locks.py
@@ -2,7 +2,6 @@
 import sys
 
 from asyncio.locks import Lock as _Lock
-from asyncio import coroutine
 
 # Fixes an issue with all Python versions that leaves pending waiters
 # without being awakened when the first waiter is canceled.
@@ -14,7 +13,7 @@
 class Lock(_Lock):
 
     if sys.version_info < (3, 7, 0):
-        @coroutine
+        @asyncio.coroutine
         def acquire(self):
             """Acquire a lock.
             This method blocks until the lock is unlocked, then sets it to
diff --git a/aioredis/pool.py b/aioredis/pool.py
index ed6933107..2ada29f9e 100644
--- a/aioredis/pool.py
+++ b/aioredis/pool.py
@@ -282,8 +282,7 @@ async def select(self, db):
         async with self._cond:
             for i in range(self.freesize):
                 res = res and (await self._pool[i].select(db))
-            else:
-                self._db = db
+            self._db = db
         return res
 
     async def auth(self, password):
diff --git a/aioredis/sentinel/pool.py b/aioredis/sentinel/pool.py
index 819ef2117..d7996909b 100644
--- a/aioredis/sentinel/pool.py
+++ b/aioredis/sentinel/pool.py
@@ -83,7 +83,7 @@ def __init__(self, sentinels, *, db=None, password=None, ssl=None,
         async def echo_events():
             try:
                 while await monitor.wait_message():
-                    ch, (ev, data) = await monitor.get(encoding='utf-8')
+                    _, (ev, data) = await monitor.get(encoding='utf-8')
                     ev = ev.decode('utf-8')
                     _logger.debug("%s: %s", ev, data)
                     if ev in ('+odown',):
@@ -295,8 +295,8 @@ async def discover_master(self, service, timeout):
                 # TODO: clear (drop) connections to schedule reconnect
                 await asyncio.sleep(idle_timeout, loop=self._loop)
                 continue
-        else:
-            raise MasterNotFoundError("No master found for {}".format(service))
+        # Otherwise
+        raise MasterNotFoundError("No master found for {}".format(service))
 
     async def discover_slave(self, service, timeout, **kwargs):
         """Perform Slave discovery for specified service."""
@@ -358,8 +358,7 @@ async def _get_slave_address(self, sentinel, service):
             if {'s_down', 'o_down', 'disconnected'} & flags:
                 continue
             return address
-        else:
-            raise BadState(state)   # XXX: only last state
+        raise BadState()   # XXX: only last state
 
     async def _verify_service_role(self, conn, role):
         res = await conn.execute(b'role', encoding='utf-8')
diff --git a/setup.py b/setup.py
index 10c2f777c..c03e8c97f 100644
--- a/setup.py
+++ b/setup.py
@@ -29,8 +29,7 @@ def read_version():
             match = regexp.match(line)
             if match is not None:
                 return match.group(1)
-        else:
-            raise RuntimeError('Cannot find version in aioredis/__init__.py')
+        raise RuntimeError('Cannot find version in {}'.format(init_py))
 
 
 classifiers = [