Wow, what a horrid and cool way to create a function that accepts generic types in Go :-)

    func add(a interface{}, b interface{}) interface{} {
      if a, ok := a.(int); ok {
        if b, ok := b.(int); ok {
          return a + b
        }
      }

      if a, ok := a.(string); ok {
        if b, ok := b.(string); ok {
          return a + b
        }
      }

      panic("incompatible types")
    }