code: def units(self, varname):
          '''return the default units of a variable'''
          if not varname in self.mapping.vars:
              raise fgFDMError('Unknown variable %s' % varname)
          return self.mapping.vars[varname].unitf units(self, varname):
          '''return the default units of a variable'''
          if not varname in self.mapping.vars:
              raise fgFDMError('Unknown variable %s' % varname)
          return self.mapping.vars[varname].units
docs: return the default units of a variable