def _register(model_name_regex: str, llm_cls: type[BaseLlm]):
    """Registers a new LLM class.

    Args:
        model_name_regex: The regex that matches the model name.
        llm_cls: The class that implements the model.
    """

    if model_name_regex in _llm_registry_dict:
      logger.info(
          'Updating LLM class for %s from %s to %s',
          model_name_regex,
          _llm_registry_dict[model_name_regex],
          llm_cls,
      )

    _llm_registry_dict[model_name_regex] = llm_cls
Registers a new LLM class.

    Args:
        model_name_regex: The regex that matches the model name.
        llm_cls: The class that implements the model.
    
src/google/adk/models/registry.py