diff --git a/src/_zkapauthorizer/config.py b/src/_zkapauthorizer/config.py
index 7ee454aad7151c6608c9ba1b321f4c29ec6e6542..c7ac61b220a100f7bb2160b7e6d3e2c808fd2666 100644
--- a/src/_zkapauthorizer/config.py
+++ b/src/_zkapauthorizer/config.py
@@ -17,20 +17,22 @@ Helpers for reading values from the Tahoe-LAFS configuration.
 """
 
 from datetime import timedelta
+
 from isodate import parse_duration
 
-from .lease_maintenance import (
-    LeaseMaintenanceConfig,
-)
+from .lease_maintenance import LeaseMaintenanceConfig
+
 
 class _EmptyConfig(object):
     """
     Weakly pretend to be a Tahoe-LAFS configuration object with no
     configuration.
     """
+
     def get_config(self, section, option, default=object(), boolean=False):
         return default
 
+
 empty_config = _EmptyConfig()
 
 
diff --git a/src/_zkapauthorizer/tests/test_lease_maintenance.py b/src/_zkapauthorizer/tests/test_lease_maintenance.py
index 2aa0740fe6c27b77319b4b45a053c95321b92db5..57a86d9497f9e1af65a9a42660dd8de0a47626d3 100644
--- a/src/_zkapauthorizer/tests/test_lease_maintenance.py
+++ b/src/_zkapauthorizer/tests/test_lease_maintenance.py
@@ -56,8 +56,8 @@ from twisted.internet.task import Clock
 from twisted.python.filepath import FilePath
 from zope.interface import implementer
 
+from ..config import empty_config, lease_maintenance_from_tahoe_config
 from ..foolscap import ShareStat
-from ..config import lease_maintenance_from_tahoe_config, empty_config
 from ..lease_maintenance import (
     LeaseMaintenanceConfig,
     MemoryMaintenanceObserver,
@@ -82,6 +82,7 @@ from .strategies import (
 
 default_lease_maint_config = lease_maintenance_from_tahoe_config(empty_config)
 
+
 def dummy_maintain_leases():
     pass