# cf.Units.isreftime

`Units.``isreftime`

  True if the units are reference time units, False otherwise.

  Note that time units (such as `'days'`) are not reference time units.

  See also

  `isdimensionless`, `islongitude`, `islatitude`, `ispressure`, `istime`

  Examples: |

      >>> print Units('days since 2000-12-1 03:00').isreftime
      True
      >>> print Units('hours since 2100-1-1', calendar='noleap').isreftime
      True
      >>> print Units(calendar='360_day').isreftime
      True
      >>> print Units('days').isreftime
      False
      >>> print Units('kg').isreftime
      False
      >>> print Units().isreftime
      False