module [0, 0] - [2, 0]
  function_definition [0, 0] - [1, 17]
    name: identifier [0, 4] - [0, 7]
    parameters: parameters [0, 7] - [0, 13]
      identifier [0, 8] - [0, 9]
      identifier [0, 11] - [0, 12]
    body: block [1, 4] - [1, 17]
      return_statement [1, 4] - [1, 16]
        binary_operator [1, 11] - [1, 16]
          left: identifier [1, 11] - [1, 12]
          right: identifier [1, 15] - [1, 16]