diff --git a/backoff/_async.py b/backoff/_async.py
index 0ca7084..82fd477 100644
--- a/backoff/_async.py
+++ b/backoff/_async.py
@@ -168,7 +168,8 @@ async def retry(*args, **kwargs):
                     await _call_handlers(on_giveup, **details, exception=e)
                     raise e
 
-                await _call_handlers(on_backoff, **details, wait=seconds, exception=e)
+                await _call_handlers(on_backoff, **details, wait=seconds,
+                                     exception=e)
 
                 # Note: there is no convenient way to pass explicit event
                 # loop to decorator, so here we assume that either default
diff --git a/backoff/_sync.py b/backoff/_sync.py
index f0bd4a1..4371e16 100644
--- a/backoff/_sync.py
+++ b/backoff/_sync.py
@@ -121,7 +121,8 @@ def retry(*args, **kwargs):
                     _call_handlers(on_giveup, **details, exception=e)
                     raise e
 
-                _call_handlers(on_backoff, **details, wait=seconds, exception=e)
+                _call_handlers(on_backoff, **details, wait=seconds,
+                               exception=e)
 
                 time.sleep(seconds)
             else: