consistency

model.py

@@ -23,7 +23,7 @@ class BertClassifier(nn.Module):
         output = self.bert(input_ids, attention_mask=attention_mask)
         logits = self.classifier(output.pooler_output)
         loss = None
-        if labels is not None:
+        if labels:
             loss_fct = nn.CrossEntropyLoss()
             loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
         return TokenClassifierOutput(loss=loss, logits=logits, hidden_states=output.hidden_states,attentions=output.attentions)