Unused, but requied target_datetime_class argument in get_data_model_types()

[thorwhalen]

Describe the bug

It's not a bug, but a code smell that led to errors on my side.

Simply put: target_datetime_class is not used in the get_data_model_types function, and yet it's a required argument.

To Reproduce

from datamodel_code_generator import DataModelType, PythonVersion, DatetimeClassType
from datamodel_code_generator.model import get_data_model_types

result = get_data_model_types(
    data_model_type=DataModelType.PydanticBaseModel, 
    target_python_version=PythonVersion.PY_39, 
)
# TypeError                                 Traceback (most recent call last)
# Cell In[15], line 5
#       2 from datamodel_code_generator.model import get_data_model_types
#       4 # Call the function
# ----> 5 result = get_data_model_types(
#       6     data_model_type=DataModelType.PydanticBaseModel, 
#       7     target_python_version=PythonVersion.PY_39, 
#       8 )
# TypeError: get_data_model_types() missing 1 required positional argument: 'target_datetime_class'"
# }

Expected behavior

I'd expect it to not fail, since the third, target_datetime_class, is not used anyway.

I'd suggest setting a default:

• target_datetime_class: Optional[DatetimeClassType] = None, since it's not used anyway. See this fork branch
• target_datetime_class: DatetimeClassType = DatetimeClassType.Datetime, if we want an actual useful choice. See this fork branch

In fact -- personally, I'd set a default for the target_python_version as well, setting it to the python version where the module is being run.
Yes, explicit over implicit, and having defaults has disadvantages, always. It does a lot for UX though.
Personally, I'd set these defaults in the format.py module, where the DataModelType and PythonVersion enums are defined, and use them throughout.

I tried, but ran into some test errors I didn't understand, so defined the defaults in model/__init__.py itself in this pull request #2196.

Version:

• OS: Sanoma
• Python version: 3.10
• datamodel-code-generator version: 0.26.3