Update on "Introduce hydra framework with backwards compatibility"

Differential Revision: [D75263989](https://our.internmc.facebook.com/intern/diff/D75263989)

[ghstack-poisoned]

Author: jackzhxng

examples/models/llama/config/llm_config.py

@@ -470,7 +470,7 @@ class LlmConfig:
     backend: BackendConfig = field(default_factory=BackendConfig)
 
     @classmethod
-    def from_args(args: argparse.Namespace) -> "LlmConfig":
+    def from_args(cls, args: argparse.Namespace) -> "LlmConfig":
         """
         To support legacy purposes, this function converts CLI args from
         argparse to an LlmConfig, which is used by the LLM export process.