<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def transformToNative(obj):
 """ Turn obj.value into a datetime.timedelta. """

        if obj.isNative:
            return obj
        obj.isNative = True
        obj.value=obj.value
        if obj.value == '':
            return obj
        else:
            deltalist=stringToDurations(obj.value)
            # When can DURATION have multiple durations?  For now:
            if len(deltalist) == 1:
                obj.value = deltalist[0]
                return obj
            else:
                raise ParseError("DURATION must have a single duration string.")