code: def run_script(self, description):
          
          targetScript = None
          for item in self.configManager.allItems:
              if item.description == description and isinstance(item, model.Script):
                  targetScript = item
  
          if targetScript is not None:
              self.runner.run_subscript(targetScript)
          else:
              raise Exception("No script with description '%s' found" % description)
docs: Run an existing script using its description to look it up
          
          Usage: C{engine.run_script(description)}
          
          @param description: description of the script to run
          @raise Exception: if the specified script does not exist