```js
// Button.stories.js

export const Primary = Template.bind({});
Primary.args ={
  primary: true,
  label: 'Button',
}
Primary.parameters = { 
  backgrounds:{
    values: [
      { name: 'red', value: '#f00', },
      { name: 'green', value: '#0f0', },
    ],
  }
};
```