diff --git a/torba/server/db.py b/torba/server/db.py
index 593bf3d83..0721dcef5 100644
--- a/torba/server/db.py
+++ b/torba/server/db.py
@@ -14,6 +14,7 @@ import array
 import ast
 import os
 import time
+from asyncio import sleep
 from bisect import bisect_right
 from collections import namedtuple
 from glob import glob
@@ -448,7 +449,7 @@ class DB:
                 return history
             self.logger.warning(f'limited_history: tx hash '
                                 f'not found (reorg?), retrying...')
-            await asyncio.sleep(0.25)
+            await sleep(0.25)
 
     # -- Undo information
 
@@ -617,7 +618,7 @@ class DB:
                 return utxos
             self.logger.warning(f'all_utxos: tx hash not '
                                 f'found (reorg?), retrying...')
-            await asyncio.sleep(0.25)
+            await sleep(0.25)
 
     async def lookup_utxos(self, prevouts):
         '''For each prevout, lookup it up in the DB and return a (hashX,
diff --git a/torba/server/mempool.py b/torba/server/mempool.py
index e3af9d154..4ae0526b1 100644
--- a/torba/server/mempool.py
+++ b/torba/server/mempool.py
@@ -11,7 +11,7 @@ import asyncio
 import itertools
 import time
 from abc import ABC, abstractmethod
-from asyncio import Lock
+from asyncio import Lock, sleep
 from collections import defaultdict
 
 import attr
@@ -117,7 +117,7 @@ class MemPool:
         while True:
             self.logger.info(f'{len(self.txs):,d} txs '
                              f'touching {len(self.hashXs):,d} addresses')
-            await asyncio.sleep(self.log_status_secs)
+            await sleep(self.log_status_secs)
             await synchronized_event.wait()
 
     async def _refresh_histogram(self, synchronized_event):
@@ -126,7 +126,7 @@ class MemPool:
             async with self.lock:
                 # Threaded as can be expensive
                 await asyncio.get_event_loop().run_in_executor(None, self._update_histogram, 100_000)
-            await asyncio.sleep(self.coin.MEMPOOL_HISTOGRAM_REFRESH_SECS)
+            await sleep(self.coin.MEMPOOL_HISTOGRAM_REFRESH_SECS)
 
     def _update_histogram(self, bin_size):
         # Build a histogram by fee rate
@@ -212,7 +212,7 @@ class MemPool:
             synchronized_event.set()
             synchronized_event.clear()
             await self.api.on_mempool(touched, height)
-            await asyncio.sleep(self.refresh_secs)
+            await sleep(self.refresh_secs)
 
     async def _process_mempool(self, all_hashes):
         # Re-sync with the new set of hashes
diff --git a/torba/server/merkle.py b/torba/server/merkle.py
index 65ebd3b8b..e8e54a06c 100644
--- a/torba/server/merkle.py
+++ b/torba/server/merkle.py
@@ -26,7 +26,7 @@
 
 '''Merkle trees, branches, proofs and roots.'''
 
-import asyncio
+from asyncio import Event
 from math import ceil, log
 
 from torba.server.hash import double_sha256
@@ -169,7 +169,7 @@ class MerkleCache:
         self.source_func = source_func
         self.length = 0
         self.depth_higher = 0
-        self.initialized = asyncio.Event()
+        self.initialized = Event()
 
     def _segment_length(self):
         return 1 << self.depth_higher
diff --git a/torba/server/peers.py b/torba/server/peers.py
index e54939af7..842111466 100644
--- a/torba/server/peers.py
+++ b/torba/server/peers.py
@@ -12,6 +12,7 @@ import random
 import socket
 import ssl
 import time
+from asyncio import Event, sleep
 from collections import defaultdict, Counter
 
 from torba.tasks import TaskGroup
@@ -150,7 +151,7 @@ class PeerManager:
                 self.logger.info(f'detected {proxy}')
                 return
             self.logger.info('no proxy detected, will try later')
-            await asyncio.sleep(900)
+            await sleep(900)
 
     async def _note_peers(self, peers, limit=2, check_ports=False,
                           source=None):
@@ -178,7 +179,7 @@ class PeerManager:
                 use_peers = new_peers
             for peer in use_peers:
                 self.logger.info(f'accepted new peer {peer} from {source}')
-                peer.retry_event = asyncio.Event()
+                peer.retry_event = Event()
                 self.peers.add(peer)
                 await self.group.add(self._monitor_peer(peer))
 
diff --git a/torba/server/session.py b/torba/server/session.py
index d80728dbf..b3b1e963e 100644
--- a/torba/server/session.py
+++ b/torba/server/session.py
@@ -16,6 +16,7 @@ import os
 import pylru
 import ssl
 import time
+from asyncio import Event, sleep
 from collections import defaultdict
 from functools import partial
 
@@ -130,7 +131,7 @@ class SessionManager:
             self.mn_cache_height = 0
             self.mn_cache = []
 
-        self.session_event = asyncio.Event()
+        self.session_event = Event()
 
         # Set up the RPC request handlers
         cmds = ('add_peer daemon_url disconnect getinfo groups log peers '
@@ -206,7 +207,7 @@ class SessionManager:
         log_interval = self.env.log_sessions
         if log_interval:
             while True:
-                await asyncio.sleep(log_interval)
+                await sleep(log_interval)
                 data = self._session_data(for_log=True)
                 for line in text.sessions_lines(data):
                     self.logger.info(line)
@@ -248,7 +249,7 @@ class SessionManager:
     async def _clear_stale_sessions(self):
         '''Cut off sessions that haven't done anything for 10 minutes.'''
         while True:
-            await asyncio.sleep(60)
+            await sleep(60)
             stale_cutoff = time.time() - self.env.session_timeout
             stale_sessions = [session for session in self.sessions
                               if session.last_recv < stale_cutoff]