README.md in webmock_method-1.0.0 vs README.md in webmock_method-1.0.1

@@ -100,9 +100,37 @@
   webmock_method :purchase, [:amount, :credit_card], lambda { |binding|
       RenderHelper.render :xml, "#{File.dirname(__FILE__)}/templates/purchase_response.xml.erb", binding
     }
 ```
 
+You can tweak you response on the fly:
+
+```ruby
+  webmock_method :purchase, [:amount, :credit_card], lambda { |binding|
+    RenderHelper.render :xml, "#{File.dirname(__FILE__)}/templates/purchase_response.xml.erb", binding
+    } do |parent, _, credit_card|
+    if credit_card.card_type == "VISA"
+      define_attribute(parent, :success,  true)
+    else
+      define_attribute(parent, :success,  false)
+      define_attribute(parent, :error_message, "Unsupported Credit Card Type")
+    end
+  end
+```
+
+and then, use new defined attributes, such as **success** and **error_message** inside your template:
+
+```xml
+<!-- stubs/templates/purchase_response.xml.erb -->
+<PurchaseResponse>
+  <Success><%= success %></Success>
+
+  <% unless success %>
+    <ErrorMessage><%= error_message %></ErrorMessage>
+  <% end %>
+</PurchaseResponse>
+```
+
 **url** parameter is optional. If you don't specify it, it will try to use **url** attribute defined
 on your service or you can define **url** parameter for WebmockMethod:
 
 ```ruby
 WebmockMethod.url = "http://api.openweathermap.org/data/2.5/weather"