code: def to_cfunits(self, unit='hours', utcoffset=None):
          
          if utcoffset is None:
              utcoffset = hydpy.pub.options.utcoffset
          string = self.to_string('iso2', utcoffset)
          string = ' '.join((string[:-6], string[-6:]))
          return f'{unit} since {string}'
docs: Return a `units` string agreeing with the NetCDF-CF conventions.
  
          By default, |Date.to_cfunits| takes `hours` as time unit, and the
          the actual value of |Options.utcoffset| as time zone information:
  
          >>> from hydpy import Date
          >>> date = Date('1992-10-08 15:15:42')
          >>> date.to_cfunits()
          'hours since 1992-10-08 15:15:42 +01:00'
  
          Other time units are allowed (no checks are performed, so select
          something useful):
  
          >>> date.to_cfunits(unit='minutes')
          'minutes since 1992-10-08 15:15:42 +01:00'
  
          For changing the time zone, pass the corresponding offset in minutes:
  
          >>> date.to_cfunits(unit='sec', utcoffset=-60)
          'sec since 1992-10-08 13:15:42 -01:00'