diff --git a/common/file.py b/common/file.py
index d0a2d5532c73ee28126afe3e12a9f9f321392efd..fb871f7a332e222f75c4cb8bdf37847492ec369a 100644
--- a/common/file.py
+++ b/common/file.py
@@ -74,12 +74,15 @@ class FileOperation:
     def get_str_num_in_file(file_name, dist_str):
         i = 1 
         dist_list = []
-        with io.open(file_name,'r') as file:
-            for item in file.readlines():
-                if dist_str in item:
-                    dist_list.append(i)
-                i = i + 1 
-        return dist_list
+        try:
+            with io.open(file_name,'r') as file:
+                for item in file.readlines():
+                    if dist_str in str(item):
+                        dist_list.append(i)
+                    i = i + 1
+            return dist_list
+        except FileNotFoundError:
+            return []
 
     @staticmethod
     def readfile(filename):