Allow to create new model with related models in Flask-Peewee API call

utils.py

def get_models_from_dictionary(model, field_dict):
    if isinstance(model, Model):
        model_instance = model
        check_fks = True
    else:
        model_instance = model()
        check_fks = False
    models = [model_instance]
    for field_name, value in field_dict.items():
        field_obj = model._meta.fields[field_name]
        if isinstance(value, dict):
            rel_obj = field_obj.to # here we can get related object type, to not be None
            if check_fks:
                try:
                    rel_obj = getattr(model, field_name) # when create rel object - it will be None
                except field_obj.to.DoesNotExist:
                    pass
                ### my add
                if rel_obj is None:
                    rel_obj = field_obj.to # RelatedOneToOneModel if new model passed as Json and not FK int Id
                ### end my add
            rel_inst, rel_models = get_models_from_dictionary(rel_obj, value)
            models.extend(rel_models)
            setattr(model_instance, field_name, rel_inst)
        else:
            setattr(model_instance, field_name, field_obj.python_value(value))
    return model_instance, models