def rest_of_key(namespace)
      return nil if @key == namespace

      key = @key.to_s

      index = key.index(namespace.to_s) && (namespace.to_s.length + 1)
      key[index, key.length].to_sym if index
    end
def rest_of_key(namespace)
      return nil if @key == namespace

      key = @key.to_s

      index = key.index(namespace.to_s) && (namespace.to_s.length + 1)
      key[index, key.length].to_sym if index
    end
Returns the rest of the key for a given namespace