attribute_changed?

# File activemodel/lib/active_model/dirty.rb, line 172
    def attribute_changed?(attr, options = {}) #:nodoc:
      result = changes_include?(attr)
      result &&= options[:to] == __send__(attr) if options.key?(:to)
      result &&= options[:from] == changed_attributes[attr] if options.key?(:from)
      result
    end