    # File lib/fog/rackspace/models/compute_v2/image.rb, line 49
            def ready?(ready_state = ACTIVE, error_states=[ERROR])
              if error_states
                error_states = Array(error_states)
                raise "Image should have transitioned to '#{ready_state}' not '#{state}'" if error_states.include?(state)
              end
              state == ready_state
            end