class Sass::Script::Operation

def operand_to_sass(op, side, opts)
  return "(#{op.to_sass(opts)})" if op.is_a?(List)
  return op.to_sass(opts) unless op.is_a?(Operation)
  pred = Sass::Script::Parser.precedence_of(@operator)
  sub_pred = Sass::Script::Parser.precedence_of(op.operator)
  assoc = Sass::Script::Parser.associative?(@operator)
  return "(#{op.to_sass(opts)})" if sub_pred < pred ||
    (side == :right && sub_pred == pred && !assoc)
  op.to_sass(opts)
end