What are closures?

Closures are a programming concept where a function retains access to its lexical scope, even when the function is executed outside that scope. In simpler terms, a closure allows a function to "remember" the environment in which it was created.

Key Features of Closures:

1. Function Inside a Function: A closure is typically created when a function is defined inside another function.
2. Access to Outer Variables: The inner function can access variables from the outer function's scope, even after the outer function has finished executing.
3. State Retention: Closures can maintain state across multiple calls.

Example in Python:

def outer_function(x):
    def inner_function():
        print(f"x from outer function: {x}")
    return inner_function

closure = outer_function(40)
closure()  # Outputs: x from outer function: 40

In this example, inner_function is a closure that remembers the value of x from outer_function. If you have more questions or need further clarification, let me know!