What specific VK Ads API endpoint would you use to programmatically create a new lookalike audience based on a pre-existing custom audience?

To programmatically create a new lookalike audience based on a pre-existing custom audience using the VK Ads API, you would use the `ads.createLookalikeRequest` endpoint. This endpoint specifically initiates the process of generating a lookalike audience, also known as a 'similar audience,' based on a source audience you provide. The source audience is typically a custom audience you've already created using data from your website, app, or CRM. The `ads.createLookalikeRequest` endpoint requires several parameters, including the ID of the VK Ads account, the ID of the source custom audience, and the desired audience size or similarity level. The API call doesn't directly return the new lookalike audience. Instead, it creates a 'lookalike request.' VK then processes this request to identify users similar to those in the source audience. Once the lookalike audience is created, it becomes available for targeting in your advertising campaigns. You can then retrieve the ID of the newly created lookalike audience using other API methods like `ads.getLookalikeRequests` or `ads.getTargetGroups`. Using the `ads.createLookalikeRequest` endpoint is the standard and most efficient method for automating the creation of lookalike audiences on VK, enabling you to scale your audience targeting efforts programmatically.