code: def convert_units(self, desired, guess=False):
          
          units._convert_units(self, desired, guess)
          return self
docs: Convert the units of the mesh into a specified unit.
  
          Parameters
          ----------
          desired : string
            Units to convert to (eg 'inches')
          guess : boolean
            If self.units are not defined should we
            guess the current units of the document and then convert?