code: def resource_type_type(loader):
      
  
      def impl(string):
          t_resources = loader.get_models('common.models#ResourceTypes')
          if set(string) - set("sco"):
              raise ValueError
          return t_resources(_str=''.join(set(string)))
  
      return impl
docs: Returns a function which validates that resource types string contains only a combination of service,
      container, and object. Their shorthand representations are s, c, and o.