# cf.CoordinateReference.canonical_units

classmethod `CoordinateReference.``canonical_units`(term)

  Return the canonical units for a standard CF coordinate conversion term.

  Parameters: | term: `str` The name of the term.
  Returns: | out: `cf.Units` or `None` The canonical units, or `None` if there are not any.
  Examples: |

      >>> cf.CoordinateReference.canonical_units('perspective_point_height')
      <CF Units: m>
      >>> cf.CoordinateReference.canonical_units('ptop')
      None