docs: def load_messages(self, directory, catalogue):
          """
          Loads translation found in a directory.
  
          @type directory: string
          @param directory: The directory to search
  
          @type catalogue: MessageCatalogue
          @param catalogue: The message catalogue to dump
  
          @raises: ValueError
          """
          if not os.path.isdir(directory):
              raise ValueError("{0} is not a directory".format(directory))
  
          for format, loader in list(self.loaders.items()):
              extension = "{0}.{1}".format(catalogue.locale, format)
              files = find_files(directory, "*.{0}".format(extension))
              for file in files:
                  domain = file.split("/")[-1][:-1 * len(extension) - 1]
                  catalogue.add_catalogue(
                      loader.load(
                          file,
                          catalogue.locale,
                          domain))