def get(key)
      return nil if !@actions.has_key?(key)
      return @results_cache[key] if @results_cache.has_key?(key)
      @results_cache[key] = @actions[key].call
    end
def get(key)
      return nil if !@actions.has_key?(key)
      return @results_cache[key] if @results_cache.has_key?(key)
      @results_cache[key] = @actions[key].call
    end
Get an action by the given key.

 This will evaluate the block given to `register` and return the resulting
 action stack.