refactor: Fit thread test condition to PEP 8

Author: GriffinCanCode

Lib/test/test_threading.py

@@ -502,7 +502,8 @@ def test_start_interrupted_after_native_start(self):
             from test.support import SHORT_TIMEOUT, threading_helper
 
             def interrupt(frame, event, arg):
-                if event == 'c_return' and arg is threading._start_joinable_thread:
+                if (event == 'c_return'
+                        and arg is threading._start_joinable_thread):
                     raise KeyboardInterrupt
 
             completed = threading.Event()