def _update_pulled_fields(instance, imported_instance, fields):
    """ Update instance fields based on imported from backend data.

        Save changes to DB only one or more fields were changed.
    """
    modified = False
    for field in fields:
        pulled_value = getattr(imported_instance, field)
        if getattr(instance, field) != pulled_value:
            setattr(instance, field, pulled_value)
            modified = True
    if modified:
        instance.save()
