How to store a closure in a struct in Rust?

Hello! I started learning Rust and encountered a problem when trying to store a closure in a struct. I have a simple calculator that should perform different operations depending on the passed closure. Here's what I'm trying to do: ```rust struct Calculator { operation: fn(i32, i32) -> i32, } fn main() { let add = |a, b| a + b; let calc = Calculator { operation: add }; println!("Result: {}", (calc.operation)(5, 3)); } ``` This code works, but only if I pass a regular function or a closure that doesn't capture variables from the outer environment. As soon as I try to use a closure that captures variables, the compiler gives an error. For example: ```rust let multiplier = 2; let multiply = |a, b| a * b * multiplier; let calc = Cal