parallel: Add missing annotation.

zerver/lib/parallel.py

@@ -12,6 +12,7 @@ def run_parallel(job, data, threads=6):
     pids = {} # type: Dict[int, Any]
 
     def wait_for_one():
+        # type: () -> Tuple[int, Any]
         while True:
             try:
                 (pid, status) = os.wait()
@@ -58,6 +59,7 @@ if __name__ == "__main__":
     jobs = [10, 19, 18, 6, 14, 12, 8, 2, 1, 13, 3, 17, 9, 11, 5, 16, 7, 15, 4]
     expected_output = [6, 10, 12, 2, 1, 14, 8, 3, 18, 19, 5, 9, 13, 11, 4, 7, 17, 16, 15]
     def wait_and_print(x):
+        # type: (int) -> int
         time.sleep(x * 0.1)
         return 0