title: Revert changes of the attributes
body: <p>I am passing 4 values from my form.</p>
  
  <pre><code>attr1
  attr2
  attr3
  attr4
  </code></pre>
  
  <p>On before_save </p>
  
  <pre><code>def before_save
    if condition == true
      # here i want to revert changes of attributes ...
      # Right now i am doing this for reverting....
      self.attr1 = self.attr1_was
      self.attr2 = self.attr2_was
    end
  end 
  </code></pre>
  
  <p>Any better way to revert changes except some attributes ?? I want to revert all the attributes except one or two ..</p>