[AIRFLOW-5746] Fix problems with static checks (#6420)

(cherry picked from commit c7ed169)

Author: potiuk

tests/dags/test_impersonation_custom.py

@@ -21,6 +21,7 @@
 
 from airflow.models import DAG
 from airflow.operators.python_operator import PythonOperator
+
 # AIRFLOW-1893 - Originally, impersonation tests were incomplete missing the use case when
 # DAGs access custom packages usually made available through the PYTHONPATH environment
 # variable. This file includes a DAG that imports a custom package made available and if
@@ -29,6 +30,7 @@
 # This DAG is used to test that impersonation propagates the PYTHONPATH environment
 # variable correctly.
 
+
 DEFAULT_DATE = datetime(2016, 1, 1)
 
 args = {
@@ -48,6 +50,7 @@ class FakeDatetime(datetime):
     def __new__(cls, *args, **kwargs):
         return datetime.__new__(datetime, *args, **kwargs)
 
+
 def print_today():
     date_time = FakeDatetime.utcnow()
     print('Today is {}'.format(date_time.strftime('%Y-%m-%d')))