behaviors_1.ex

defmodule Calculator do
  use Tracer

  def concat(a, b) do
    IO.puts a <> b
  end

  def puts_sum_three(a, b, c) do
    IO.puts a + b + c
  end
end

Calculator.puts_sum_three(1, 2, 3)
# ==> 'call   puts_sum_three(1, 2, 3)'
# 6
# <== 'returns 6'