models/__init__.py

import glob
import importlib
import logging
import os.path as osp

# automatically scan and import model modules
# scan all the files under the 'models' folder and collect files ending with
# '_model.py'
model_folder = osp.dirname(osp.abspath(__file__))
model_filenames = [
    osp.splitext(osp.basename(v))[0]
    for v in glob.glob(f'{model_folder}/*_model.py')
]
# import all the model modules
_model_modules = [
    importlib.import_module(f'models.{file_name}')
    for file_name in model_filenames
]


def create_model(opt):
    """Create model.

    Args:
        opt (dict): Configuration. It constains:
            model_type (str): Model type.
    """
    model_type = opt['model_type']

    # dynamically instantiation
    for module in _model_modules:
        model_cls = getattr(module, model_type, None)
        if model_cls is not None:
            break
    if model_cls is None:
        raise ValueError(f'Model {model_type} is not found.')

    model = model_cls(opt)

    logger = logging.getLogger('base')
    logger.info(f'Model [{model.__class__.__name__}] is created.')
    return model