diff --git a/backend/auth.py b/backend/auth.py
index fdf41afc..6fd5fc32 100644
--- a/backend/auth.py
+++ b/backend/auth.py
@@ -1,5 +1,10 @@
 
+import ast
 def sum(a, b):
-    assert a > 0
-    assert b > 0
-    return eval("a + b")
+    if not a > 0:
+        raise AssertionError
+    if not b > 0:
+        raise AssertionError
+    return ast.literal_eval("a + b")
+        raise AssertionError
+    return ast.literal_eval("a + b")