(Program
  (ExpressionStatements
    (Function
      (Params
      {-(Other "required_parameter"
          (Identifier))-}
        (Other "required_parameter"
          (Identifier))
      {+(Other "required_parameter"
          (Identifier))+})
      (Return
        (MathOperator
        { (Identifier)
        ->(Identifier) }
        { (Other "+")
        ->(Other "*") }
        { (Identifier)
        ->(Identifier) })))))