chore: LLM - Improved the typing of the from_pretrained method

PiperOrigin-RevId: 540099054

Author: Ark-kun

vertexai/_model_garden/_model_garden_models.py

@@ -16,7 +16,7 @@
 """Base class for working with Model Garden models."""
 
 import dataclasses
-from typing import Dict, Optional, Type
+from typing import Dict, Optional, Type, TypeVar
 
 from google.cloud import aiplatform
 from google.cloud.aiplatform import base
@@ -44,6 +44,8 @@
 
 _LOGGER = base.Logger(__name__)
 
+T = TypeVar("T", bound="_ModelGardenModel")
+
 
 @dataclasses.dataclass
 class _ModelInfo:
@@ -180,7 +182,7 @@ def __init__(self, model_id: str, endpoint_name: Optional[str] = None):
         )
 
     @classmethod
-    def from_pretrained(cls, model_name: str) -> "_ModelGardenModel":
+    def from_pretrained(cls: Type[T], model_name: str) -> T:
         """Loads a _ModelGardenModel.
 
         Args: