feat: promote ModelExtractor

ju/__init__.py

@@ -5,6 +5,7 @@
 from ju.json_schema import function_to_json_schema, json_schema_to_signature
 from ju.util import truncate_dict_values
 from ju.pydantic_util import (
+    ModelExtractor,  # Extracts key paths and corresponding values from data based on matching Pydantic models.
     is_valid_wrt_model,
     valid_models,
     data_to_pydantic_model,  # data to pydantic model

ju/pydantic_util.py

@@ -573,6 +573,9 @@ def recurse_model(model: Type[BaseModel], prefix: str = '') -> Dict[str, Type[An
 from pydantic import BaseModel
 
 
+# TODO: Not sure the use of ObjectClassifier and is_valid_wrt_model is a good thing
+#   here. We could just directly implement the logic of it to be more explicit and
+#   self-contained. We would then not need verifiers and model_classifier.
 @dataclass
 class ModelExtractor:
     """