docs: 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
          --------
          >>> import xarray as xr
          >>> times = xr.cftime_range('2000', periods=2, calendar='gregorian')
          >>> times
          CFTimeIndex([2000-01-01 00:00:00, 2000-01-02 00:00:00], dtype='object')
          >>> times.to_datetimeindex()
          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)