diff --git a/tools/migratedb/import_redis.py b/tools/migratedb/import_redis.py
index ab587d6..1e1abda 100644
--- a/tools/migratedb/import_redis.py
+++ b/tools/migratedb/import_redis.py
@@ -24,7 +24,10 @@ def writeToRedis(conn, cmdline):
     elif cmdline[0] == 'sadd':
         conn.sadd(cmdline[1], cmdline[2])
     elif cmdline[0] == 'set':
-        conn.set(cmdline[1], cmdline[2])
+        if cmdline[2] != None:
+            conn.set(cmdline[1], cmdline[2])
+        else:
+            print('[warning]', cmdline)
     elif cmdline[0] == 'expire':
         conn.expire(cmdline[1], cmdline[2])
     else: