Mixtral models throw the following exception
```
Traceback (most recent call last):
File "<frozen runpy>", line 198, in _run_module_as_main
File "<frozen runpy>", line 88, in _run_code
File "/opt/homebrew/anaconda3/lib/python3.11/site-packages/mlx_lm/generate.py", line 119, in <module>
main(args)
File "/opt/homebrew/anaconda3/lib/python3.11/site-packages/mlx_lm/generate.py", line 96, in main
model, tokenizer = load(args.model, tokenizer_config=tokenizer_config)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/anaconda3/lib/python3.11/site-packages/mlx_lm/utils.py", line 278, in load
model = load_model(model_path)
^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/anaconda3/lib/python3.11/site-packages/mlx_lm/utils.py", line 221, in load_model
model_class, model_args_class = _get_classes(config=config)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/anaconda3/lib/python3.11/site-packages/mlx_lm/utils.py", line 46, in _get_classes
arch = importlib.import_module(f"mlx_lm.models.{model_type}")
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/anaconda3/lib/python3.11/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 940, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "/opt/homebrew/anaconda3/lib/python3.11/site-packages/mlx_lm/models/mixtral.py", line 11, in <module>
@dataclass
^^^^^^^^^
File "/opt/homebrew/anaconda3/lib/python3.11/dataclasses.py", line 1230, in dataclass
return wrap(cls)
^^^^^^^^^
File "/opt/homebrew/anaconda3/lib/python3.11/dataclasses.py", line 1220, in wrap
return _process_class(cls, init, repr, eq, order, unsafe_hash,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/anaconda3/lib/python3.11/dataclasses.py", line 1027, in _process_class
_init_fn(all_init_fields,
File "/opt/homebrew/anaconda3/lib/python3.11/dataclasses.py", line 545, in _init_fn
raise TypeError(f'non-default argument {f.name!r} '
TypeError: non-default argument 'model_type' follows default argument
```
* lazy model import in mlx_lm
* change lora loading
* fix olmo lora
* remove a bunch of unused stuff from plamo
* move phixtral to mlx-lm and out of llms/
