diff --git a/activitysim/abm/models/non_mandatory_tour_frequency.py b/activitysim/abm/models/non_mandatory_tour_frequency.py
index d158f9e64..ec790ce7f 100644
--- a/activitysim/abm/models/non_mandatory_tour_frequency.py
+++ b/activitysim/abm/models/non_mandatory_tour_frequency.py
@@ -11,7 +11,10 @@
 import pandas as pd
 
 from activitysim.abm.models.util import annotate
-from activitysim.abm.models.util.overlap import person_max_window, person_available_periods
+from activitysim.abm.models.util.overlap import (
+    person_max_window,
+    person_available_periods,
+)
 from activitysim.abm.models.util.school_escort_tours_trips import (
     recompute_tour_count_statistics,
 )
diff --git a/activitysim/abm/models/util/overlap.py b/activitysim/abm/models/util/overlap.py
index 8faf3af34..a7c102a56 100644
--- a/activitysim/abm/models/util/overlap.py
+++ b/activitysim/abm/models/util/overlap.py
@@ -278,7 +278,9 @@ def calculate_consecutive(array):
     return out
 
 
-def person_available_periods(state: workflow.State, persons, start_bin=None, end_bin=None, continuous=False):
+def person_available_periods(
+    state: workflow.State, persons, start_bin=None, end_bin=None, continuous=False
+):
     """
     Returns the number of available time period bins foreach person in persons.
     Can limit the calculation to include starting and/or ending bins.