class Sass::Tree::PropNode

def val_to_sass_concat(node, opts)
  return node unless node.is_a?(Sass::Script::Operation)
  return val_to_sass_div(node, opts) unless node.operator == :space
  Sass::Script::Operation.new(
    val_to_sass_div(node.operand1, opts),
    val_to_sass_concat(node.operand2, opts),
    node.operator)
end