diff --git a/smash/web/api_views/appointment.py b/smash/web/api_views/appointment.py
index e7b8f17bc06df1be8041a9aa908949d3fc311d16..95e555009efb8a5e45278b81df4a1cefc86106f2 100644
--- a/smash/web/api_views/appointment.py
+++ b/smash/web/api_views/appointment.py
@@ -184,8 +184,9 @@ def serialize_appointment(appointment: Appointment):
         nd_number = study_subject.nd_number
         screening_number = study_subject.screening_number
         subject_type = study_subject.type.name
-        phone_numbers = ", ".join([_f for _f in [study_subject.subject.phone_number, study_subject.subject.phone_number_2,
-                                          study_subject.subject.phone_number_3] if _f])
+        phone_numbers = ", ".join([_f for _f in [study_subject.subject.phone_number,
+                                                 study_subject.subject.phone_number_2,
+                                                 study_subject.subject.phone_number_3] if _f])
         appointment_type_names = ", ".join(
             [str(appointment_type_codes) for appointment_type_codes in appointment.appointment_types.all()])
     else: