diff --git a/src/sentiment.jl b/src/sentiment.jl
index 4bcffd6..c64d1e8 100644
--- a/src/sentiment.jl
+++ b/src/sentiment.jl
@@ -8,6 +8,8 @@ function pad_sequences(l, maxlen=500)
             push!(res, ele)
         end
         return res
+    else
+        throw("String length exceeds maximum length.")
     end
 end