Update app.py

app.py

@@ -5,7 +5,7 @@
 # LICENSE file in the root directory of this source tree.
 
 import argparse
-from concurrent.futures import ProcessPoolExecutor
+from concurrent.futures import ThreadPoolExecutor
 import logging
 import os
 from pathlib import Path
@@ -44,7 +44,7 @@ def _call_nostderr(*args, **kwargs):
 
 sp.call = _call_nostderr
 # Preallocating the pool of processes.
-pool = ProcessPoolExecutor(4)
+pool = ThreadPoolExecutor(4)
 pool.__enter__()