Replace assert statements with raise exceptions (#20478)

* replace assert statements with exceptions

* made conditions more readable

src/transformers/data/metrics/squad_metrics.py

@@ -536,7 +536,8 @@ def compute_predictions_logits(
         if not nbest:
             nbest.append(_NbestPrediction(text="empty", start_logit=0.0, end_logit=0.0))
 
-        assert len(nbest) >= 1, "No valid predictions"
+        if len(nbest) < 1:
+            raise ValueError("No valid predictions")
 
         total_scores = []
         best_non_null_entry = None
@@ -557,7 +558,8 @@ def compute_predictions_logits(
             output["end_logit"] = entry.end_logit
             nbest_json.append(output)
 
-        assert len(nbest_json) >= 1, "No valid predictions"
+        if len(nbest_json) < 1:
+            raise ValueError("No valid predictions")
 
         if not version_2_with_negative:
             all_predictions[example.qas_id] = nbest_json[0]["text"]
@@ -752,8 +754,10 @@ def compute_predictions_log_probs(
             output["end_log_prob"] = entry.end_log_prob
             nbest_json.append(output)
 
-        assert len(nbest_json) >= 1, "No valid predictions"
-        assert best_non_null_entry is not None, "No valid predictions"
+        if len(nbest_json) < 1:
+            raise ValueError("No valid predictions")
+        if best_non_null_entry is None:
+            raise ValueError("No valid predictions")
 
         score_diff = score_null
         scores_diff_json[example.qas_id] = score_diff