fix linting issues

backend/experiment/rules/huang_2022.py

@@ -232,6 +232,7 @@ def final_score_message(self, session):
         ]
         return " ".join([str(m) for m in messages])
 
+
 def get_test_playback():
     from section.models import Section
     test_section = Section.objects.get(song__name='audiocheck')

backend/experiment/rules/matching_pairs.py

@@ -12,6 +12,7 @@
 
 from section.models import Section
 
+
 class MatchingPairsGame(Base):
     ID = 'MATCHING_PAIRS'
     num_pairs = 8

backend/experiment/tests/test_utils.py

@@ -2,6 +2,7 @@
 
 from experiment.utils import create_player_labels
 
+
 class TestExperimentUtils(TestCase):
 
     def test_create_player_labels(self):

backend/experiment/utils.py

@@ -1,5 +1,6 @@
 import roman
 
+
 def serialize(actions):
     ''' Serialize an array of actions '''
     if isinstance(actions, list):
@@ -30,9 +31,11 @@ def external_url(text, url):
     # Create a HTML element for an external url
     return '<a href="{}" target="_blank" rel="noopener noreferrer" >{}</a>'.format(url, text)
 
+
 def create_player_labels(num_labels, label_style='number'):
     return [format_label(i, label_style) for i in range(num_labels)]
 
+
 def format_label(number, label_style):
     if label_style == 'alphabetic':
         return chr(number + 65)