def populate_default_values(cls, new_kwargs: Dict) -> Dict:
        """
        Receives dictionary of model that is about to be saved and populates the default
        value on the fields that have the default value set, but no actual value was
        passed by the user.

        :param new_kwargs: dictionary of model that is about to be saved
        :type new_kwargs: Dict
        :return: dictionary of model that is about to be saved
        :rtype: Dict
        """
        for field_name, field in cls.ormar_config.model_fields.items():
            if field_name not in new_kwargs and field.has_default(use_server=False):
                new_kwargs[field_name] = field.get_default()
            # clear fields with server_default set as None
            if (
                field.server_default is not None
                and new_kwargs.get(field_name, None) is None
            ):
                new_kwargs.pop(field_name, None)
        return new_kwargs

        Receives dictionary of model that is about to be saved and populates the default
        value on the fields that have the default value set, but no actual value was
        passed by the user.

        :param new_kwargs: dictionary of model that is about to be saved
        :type new_kwargs: Dict
        :return: dictionary of model that is about to be saved
        :rtype: Dict
        
ormar/models/mixins/save_mixin.py