code: def has(self, id, domain):
          
          assert isinstance(id, (str, unicode))
          assert isinstance(domain, (str, unicode))
  
          if self.defines(id, domain):
              return True
  
          if self.fallback_catalogue is not None:
              return self.fallback_catalogue.has(id, domain)
  
          return False
docs: Checks if a message has a translation.
  
          @rtype: bool
          @return: true if the message has a translation, false otherwise