_You can follow along with the video course from here._ ### Introduction When you encounter a part that's not very clear, an AI or forum can help provide a comprehensive understanding of the topic at hand. In this lesson, we will learn how to craft effective questions and prompts. ### getVersion function For example, consider the mechanism behind the **Interface** construct: ````markdown How does this solidity function return the value `4` when I didn't define any logic in AggregatorV3Interface? ``` function getVersion() public view returns (uint256) { return AggregatorV3Interface(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419).version(); } ``` ```` Here is the answer ChatGPT 3.5 provides: ```markdown In the code you provided, the `getVersion()` function is calling the `version()` function of an instance of the `AggregatorV3Interface` contract. It appears that the contract address `0x694AA1769357215DE4FACO81bf1E309aDC325306` is being used to create an instance of the `AggregatorV3Interface`. The `AggregatorV3Interface` is an interface contract that defines a set of functions that must be implemented by another contract. It serves as a way to interact with the contract at the given address by providing a common interface. The `version()` function is called in your code is likely defined in the actual contract that implements the `AggregatorV3Interface`. This implementation contract is deployed at the specified address and is expected to have a `version()` function that returns a `uint256` value. So, the code you provided is creating an instance of the `AggregatorV3Interface` contract at the given address and then calling its `version()` function to retrieve a `uint256` value. If the implementation contract at that address has a `version()` function that returns `4`, then the `getVersion()` function will return `4` as well. ``` By _type casting_ the address to the interface, we are indicating to the Solidity compiler that there is a `version` function available at that address. ### Asking more questions Since AIs excel at maintaining context, we can easily **follow up** on this answer. ```markdown What would happen if that contract address didn't have that function? ``` As explained by the AI: ```markdown If the implementation contract at the given address does not have a `version()` function or if it has a different function signature, calling `version()` on that contract will result in a compilation error or a runtime error. ``` > 🚧 **WARNING**:br > Always verify AI-provided information by consulting a discussion forum ### Conclusion By leveraging AI and discussion forums, you can gain a deeper understanding of complex topics and ensure your questions are thoroughly addressed. ### 🧑‍💻 Test yourself 1. 📕 Delve deeper into the `getVersion` function by asking AI three more questions about it