docs: def build_backend(self, conn_string):
          """
          Given a DSN, returns an instantiated backend class.
  
          Ex::
  
              backend = gator.build_backend('locmem://')
              # ...or...
              backend = gator.build_backend('redis://127.0.0.1:6379/0')
  
          :param conn_string: A DSN for connecting to the queue. Passed along
              to the backend.
          :type conn_string: string
  
          :returns: A backend ``Client`` instance
          """
          backend_name, _ = conn_string.split(':', 1)
          backend_path = 'alligator.backends.{}_backend'.format(backend_name)
          client_class = import_attr(backend_path, 'Client')
          return client_class(conn_string)