diff --git a/code/database.py b/code/database.py
index 800deb1..5eb535f 100644
--- a/code/database.py
+++ b/code/database.py
@@ -25,7 +25,7 @@ def connect(
     # load environment variables
     load_dotenv()
     ip_addr = os.getenv(
-        'DB_IP_ADDRESS', 
+        'DB_IP_ADDRESS',
         default=DB_IP_ADDRESS
     )
     db_name = os.getenv(
diff --git a/code/initialise_app.py b/code/initialise_app.py
index ba0a63b..973ae74 100644
--- a/code/initialise_app.py
+++ b/code/initialise_app.py
@@ -27,7 +27,11 @@ def initialise_app(
     """
     # load environment variables
     load_dotenv()
-    assert 'USER_ID' in os.environ, 'environment variable USER_ID must be specified'
+    assert (
+        'USER_ID' in os.environ
+    ), (
+        'environment variable USER_ID must be specified'
+    )
     logger_level = os.getenv(
         'LOGGER_LEVEL',
         default=LOGGER_LEVEL
diff --git a/code/main.py b/code/main.py
index 0ef9e24..ee07606 100644
--- a/code/main.py
+++ b/code/main.py
@@ -123,7 +123,7 @@ if __name__ == '__main__':
             )
         # extra data flush
         if (
-            time.time() >= data_flush_time and 
+            time.time() >= data_flush_time and
             data_queue.qsize() > 0
         ):
             logging.debug('triggered extra data flush')