def _flatten_serializer_errors_to_list(serializer_errors):
    """
    Flatten DRF Serializer validation errors to a list with one field per item.
    """
    field_errors = []
    for field_name, details in serializer_errors.items():
        details_string = ','.join([str(detail) for detail in details])
        field_errors.append(f'{field_name}: {details_string}')
    return field_errors