code: def import_variables(self, container, varnames=None):
          
          if varnames is None:
              for keyword in self.tkvariables:
                  setattr(container, keyword, self.tkvariables[keyword])
          else:
              for keyword in varnames:
                  if keyword in self.tkvariables:
                      setattr(container, keyword, self.tkvariables[keyword])
docs: Helper method to avoid call get_variable for every variable.