12.1.1 First-class functions

• What is functional programming primarily based on?

  Mathematical functions
• In functional programming, variables and data structures are considered immutable
• Pure functions in functional programming have side effects.

  False
• What are higher-order functions in functional programming?

  Functions accepting other functions
• In the example code, the `apply_operation` function is a higher-order function because it takes another function as an argument
• First-class functions can be assigned to variables.
• First-class functions can be passed as arguments to other functions
• What does the expression `def create_function(): return \lambda x: x + 1` return?

  A function
• First-class functions enhance code reusability.
• In the example code, the `apply_operation` function uses the first-class function `add` as an argument
• What does the `create_multiplier` function return?

  A function
• First-class functions can be returned from other functions.
• What is the output of the `double` function when called with the argument 5?

  10
• The `create_multiplier` function creates a new function called multiplier