anchor.diff:  /// Writes an XmlDocument to a config file.
   /// ## Parameters
   ///  - `fileName` - The file name of the config file.
  -///  - `config` - The XElement representing the config.
  +///  - `config` - The XmlDocument representing the config.
   let writeConfig (fileName:string) (config:XmlDocument) = config.Save fileName 
   
   /// Reads a config file from the given file name, replaces an attribute using the given xPath and writes it back.
  
positive.code: ///  - `key` - The AppSettings attribute key name for which the value should be replaced.
  ///  - `value` - The new AppSettings attribute value.
  ///  - `fileName` - The file name of the config file.
  let updateAppSetting key value fileName =
      updateConfigSetting fileName ("appSettings/add[@key='" + key + "']") "value" value
  
  
negative.code: /// Contains functions which allow to read and write config files.
  module Fake.ConfigurationHelper
      
  open System.Xml
  open System.Xml.Linq
  
  /// Reads a config file into an XmlDocument.
  /// ## Parameters
  