Add docstrings to new HUB functions (#7576)

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

ultralytics/hub/session.py

@@ -68,7 +68,7 @@ class HUBTrainingSession:
             self.model = self.client.model()  # load empty model
 
     def load_model(self, model_id):
-        # Initialize model
+        """Loads an existing model from Ultralytics HUB using the provided model identifier."""
         self.model = self.client.model(model_id)
         if not self.model.data:  # then model model does not exist
             raise ValueError(emojis(f"❌ The specified HUB model does not exist"))  # TODO: improve error handling
@@ -82,7 +82,7 @@ class HUBTrainingSession:
         LOGGER.info(f"{PREFIX}View model at {self.model_url} 🚀")
 
     def create_model(self, model_args):
-        # Initialize model
+        """Initializes a HUB training session with the specified model identifier."""
         payload = {
             "config": {
                 "batchSize": model_args.get("batch", -1),
@@ -168,6 +168,7 @@ class HUBTrainingSession:
         return api_key, model_id, filename
 
     def _set_train_args(self, **kwargs):
+        """Initializes training arguments and creates a model entry on the Ultralytics HUB."""
         if self.model.is_trained():
             # Model is already trained
             raise ValueError(emojis(f"Model is already trained and uploaded to {self.model_url} 🚀"))
@@ -179,6 +180,7 @@ class HUBTrainingSession:
         else:
             # Model has no saved weights
             def get_train_args(config):
+                """Parses an identifier to extract API key, model ID, and filename if applicable."""
                 return {
                     "batch": config["batchSize"],
                     "epochs": config["epochs"],
@@ -213,6 +215,7 @@ class HUBTrainingSession:
         **kwargs,
     ):
         def retry_request():
+            """Attempts to call `request_func` with retries, timeout, and optional threading."""
             t0 = time.time()  # Record the start time for the timeout
             for i in range(retry + 1):
                 if (time.time() - t0) > timeout:
@@ -254,7 +257,7 @@ class HUBTrainingSession:
             return retry_request()
 
     def _should_retry(self, status_code):
-        # Status codes that trigger retries
+        """Determines if a request should be retried based on the HTTP status code."""
         retry_codes = {
             HTTPStatus.REQUEST_TIMEOUT,
             HTTPStatus.BAD_GATEWAY,