'Convert to formal string, for repr().
>>> dt = datetime(2010, 1, 1)
>>> repr(dt)
\'datetime.datetime(2010, 1, 1, 0, 0)\'
>>> dt = datetime(2010, 1, 1, tzinfo=timezone.utc)
>>> repr(dt)
\'datetime.datetime(2010, 1, 1, 0, 0, tzinfo=datetime.timezone.utc)\''

def __repr__(self):

    return ('%s(%d,    %d,    %d)' % (('datetime.' + self.__class__.__name__), self._year, self._month, self._day))
