[CI] fix a few lint errors

timer.py

@@ -1,5 +1,9 @@
 #!/usr/bin/python
 
+"""
+OBS countdown timer for OBS
+"""
+
 import argparse
 import os
 import time
@@ -13,15 +17,16 @@ args = parser.parse_args()
 
 
 def write_countdown(filename, stimer):
-    t = stimer
-    with open(filename, 'w') as f:
-        while t > 0:
-            t -= 1
-            min, sec = divmod(t, 60)
-            print(f'{min:02d}:{sec:02d}')
-            f.seek(0)
-            f.write(f'{min:02d}:{sec:02d}')
-            os.fsync(f)
+    """ decrease counter anf write synchronously to dest file """
+    tsec = stimer
+    with open(filename, 'w') as destfile:
+        while tsec > 0:
+            tsec -= 1
+            minutes, sec = divmod(tsec, 60)
+            print(f'{minutes:02d}:{sec:02d}')
+            destfile.seek(0)
+            destfile.write(f'{minutes:02d}:{sec:02d}')
+            os.fsync(destfile)
             time.sleep(1)