<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def to_datetimeindex(self, unsafe=False):
 """If possible, convert this index to a pandas.DatetimeIndex. Parameters unsafe : bool Flag to turn off warning when converting from a CFTimeIndex with a non-standard calendar to a DatetimeIndex (default ``False``). Returns ------- pandas.DatetimeIndex Raises ------ ValueError If the CFTimeIndex contains dates that are not possible in the standard calendar or outside the pandas.Timestamp-valid range. Warns ----- RuntimeWarning If converting from a non-standard calendar to a DatetimeIndex. Warnings -------- Note that for non-standard calendars, this will change the calendar type of the index. In that case the result of this method should be used with caution. Examples -------- CFTimeIndex([2000-01-01 00:00:00, 2000-01-02 00:00:00], dtype='object') DatetimeIndex(['2000-01-01', '2000-01-02'], dtype='datetime64[ns]', freq=None) """
  # noqa: E501
        nptimes = cftime_to_nptime(self)
        calendar = infer_calendar_name(self)
        if calendar not in _STANDARD_CALENDARS and not unsafe:
            warnings.warn(
                'Converting a CFTimeIndex with dates from a non-standard '
                'calendar, {!r}, to a pandas.DatetimeIndex, which uses dates '
                'from the standard calendar.  This may lead to subtle errors '
                'in operations that depend on the length of time between '
                'dates.'.format(calendar), RuntimeWarning, stacklevel=2)
        return pd.DatetimeIndex(nptimes)