code: def get_backend(alias):
      
      if alias not in settings.BACKENDS:
          raise VCSError("Given alias '%s' is not recognized! Allowed aliases:\n"
              "%s" % (alias, pformat(settings.BACKENDS.keys())))
      backend_path = settings.BACKENDS[alias]
      klass = import_class(backend_path)
      return klass
docs: Returns ``Repository`` class identified by the given alias or raises
      VCSError if alias is not recognized or backend class cannot be imported.