storybook/docs/snippets/svelte/component-story-custom-args-complex.js.mdx

```js
// YourComponent.stories.js

import YourComponent from './YourComponent.svelte';

export default {
  title: 'A complex case with a function',
  component: YourComponent,
  //👇 Creates specific argTypes
  argTypes: {
    propertyA: {
      options: ['Item One', 'Item Two', 'Item Three'],
      control: { type: 'select' }, // Automatically inferred when 'options' is defined
    },
    propertyB: {
      options: ['Another Item One', 'Another Item Two', 'Another Item Three'],
    },
  },
};

//👇 Some function to demonstrate the behavior
const someFunction = (valuePropertyA, valuePropertyB) => {
  // Makes some computations and returns something
};

const Template = (args) => {
  const { propertyA, propertyB } = args;
  
  //👇 Assigns the function result to a variable
  const someFunctionResult = someFunction(propertyA, propertyB);
  return {
    Component: YourComponent,
    props: {
      ...args,
      someProperty: someFunctionResult,
    },
  };
};
```