cdm/src/main/java/ucar/nc2/units/SimpleUnit.java
public boolean isUnknownUnit() {
    ucar.units.Unit uu = getUnit();
    if (uu instanceof ucar.units.UnknownUnit)
      return true;
    if (uu instanceof ucar.units.DerivedUnit)
      return isUnknownUnit((ucar.units.DerivedUnit) uu);
    if (uu instanceof ucar.units.ScaledUnit) {
      ucar.units.ScaledUnit scu = (ucar.units.ScaledUnit) uu;
      Unit u = scu.getUnit();
      if (u instanceof ucar.units.UnknownUnit)
        return true;

      if (u instanceof ucar.units.DerivedUnit)
        return isUnknownUnit((ucar.units.DerivedUnit) u);
    }
    return false;
  }
public boolean isUnknownUnit() {
    ucar.units.Unit uu = getUnit();
    if (uu instanceof ucar.units.UnknownUnit)
      return true;
    if (uu instanceof ucar.units.DerivedUnit)
      return isUnknownUnit((ucar.units.DerivedUnit) uu);
    if (uu instanceof ucar.units.ScaledUnit) {
      ucar.units.ScaledUnit scu = (ucar.units.ScaledUnit) uu;
      Unit u = scu.getUnit();
      if (u instanceof ucar.units.UnknownUnit)
        return true;

      if (u instanceof ucar.units.DerivedUnit)
        return isUnknownUnit((ucar.units.DerivedUnit) u);
    }
    return false;
  }
Is this an instance of an UnknownUnit?

@return true if an instance of an UnknownUnit