def possible_namespaces
      namespaces = []
      key = @key.to_s
      while (index = key.rindex('_'))
        key = key[0, index]
        namespaces << key.to_sym
      end
      namespaces
    end
def possible_namespaces
      namespaces = []
      key = @key.to_s
      while (index = key.rindex('_'))
        key = key[0, index]
        namespaces << key.to_sym
      end
      namespaces
    end
Returns an array of possible namespaces based on splitting the key at
 every underscore.