Parallelism must be at least 1.
@@ -57,6 +57,7 @@ def _set_default_executor(loop, parallelism: Optional[int]):
'''configure this event loop to respect the settings provided.'''
if parallelism is None:
return
+ parallelism = max(parallelism, 1)
exec = ThreadPoolExecutor(max_workers=parallelism)
loop.set_default_executor(exec)
