diff --git a/modeling.py b/modeling.py
index a7d719cfb..713be5637 100644
--- a/modeling.py
+++ b/modeling.py
@@ -233,7 +233,7 @@ def relative_positional_encoding(qlen, klen, d_model, clamp_len, attn_type,
 
     if bsz is not None:
       # With bi_data, the batch size should be divisible by 2.
-      assert bsz%2 == 0
+      tf.debugging.assert_equal(bsz % 2, 0)
       fwd_pos_emb = positional_embedding(fwd_pos_seq, inv_freq, bsz//2)
       bwd_pos_emb = positional_embedding(bwd_pos_seq, inv_freq, bsz//2)
     else: