chore: LLM - TextEmbeddingModel - Added argument type checking

PiperOrigin-RevId: 580022424

Author: Ark-kun

tests/unit/aiplatform/test_language_models.py

@@ -3567,6 +3567,10 @@ def test_text_embedding_ga(self):
                 assert len(vector) == _TEXT_EMBEDDING_VECTOR_LENGTH
                 assert vector == _TEST_TEXT_EMBEDDING_PREDICTION["embeddings"]["values"]
 
+        # Validating that a single string is not accepted.
+        with pytest.raises(TypeError):
+            model.get_embeddings("What is life?")
+
     def test_batch_prediction(
         self,
         get_endpoint_mock,

vertexai/language_models/_language_models.py

@@ -1520,6 +1520,10 @@ def _prepare_text_embedding_request(
         Returns:
             A `_MultiInstancePredictionRequest` object.
         """
+        if isinstance(texts, str) or not isinstance(texts, Sequence):
+            raise TypeError(
+                "The `texts` argument must be a list, not a single string."
+            )
         instances = []
         for text in texts:
             if isinstance(text, TextEmbeddingInput):