<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def replace(self, year=None, month=None, day=None, hour=None, minute=None, second=None, microsecond=None, tzinfo=None):
 """ Returns a new datetime.datetime or asn1crypto.util.extended_datetime object with the specified components replaced :return: A datetime.datetime or asn1crypto.util.extended_datetime object """


        if year is None:
            year = self.year
        if month is None:
            month = self.month
        if day is None:
            day = self.day
        if hour is None:
            hour = self.hour
        if minute is None:
            minute = self.minute
        if second is None:
            second = self.second
        if microsecond is None:
            microsecond = self.microsecond
        if tzinfo is None:
            tzinfo = self.tzinfo

        if year > 0:
            cls = datetime
        else:
            cls = extended_datetime

        return cls(
            year,
            month,
            day,
            hour,
            minute,
            second,
            microsecond,
            tzinfo
        )