def METHOD_NAME(self):
    for param in self.paramlst:
        w = self.widgets[param.name]
        value = self.get_widget_value(w, param)
        if ('type' in param) and (value is not None):
            # hack
            if value == 'None':
                value = None
            else:
                value = param.type(value)
        setattr(self.obj, param.name, value)