Swift protocols and extensions?

Example:

  protocol Describable {
      func describe() -> String
  }
  extension Int: Describable {
      func describe() -> String {
          return "This is the number (self)"
      }
  }
  print(5.describe())  // Outputs: This is the number 5
  

Solution:

Protocols define a blueprint of methods, properties, and other requirements for a particular task. Extensions add new functionality to an existing class, structure, enumeration, or protocol type.