code: def get_one_required(self, locator):
          
          components = self.find(locator, True)
          return components[0] if len(components) > 0 else None
docs: Gets a required component reference that matches specified locator.
  
           :param locator: the locator to find a reference by.
  
           :return: a matching component reference.
  
           :raises: a [[ReferenceException]] when no references found.