diff --git a/soitool/serialize_export_import_soi.py b/soitool/serialize_export_import_soi.py
index 8e5356c6d4a93520e2f60a71e904da96a08aef9a..e2cce5be6d4ae8add2f2eaf9d3b73d01ed696bef 100644
--- a/soitool/serialize_export_import_soi.py
+++ b/soitool/serialize_export_import_soi.py
@@ -134,7 +134,7 @@ def import_soi(file_path):
         If 'type' of module or attachment is not implemented.
     """
     with open(file_path, "r") as file:
-        if file_path[-4::] == ".txt":
+        if file_path.endswith(".txt"):
             serialized = literal_eval(decompress(file.read()))
         else:
             serialized = literal_eval(file.read())