```ruby
module AFMotion
  class HTTPResult
    attr_accessor :operation, :object, :error

    def initialize(operation, responseObject, error)
      self.operation = operation
      self.object = responseObject
      self.error = error
    end

    def success?
      !failure?
    end

    def failure?
      !!error
    end

    def body
      if operation && operation.responseData
        NSString.stringWithUTF8String(operation.responseData.bytes)
      end
    end
  end
end
```

Change to use AFNetworking's API
user
```ruby
module AFMotion
  class HTTPResult
    attr_accessor :operation, :object, :error

    def initialize(operation, responseObject, error)
      self.operation = operation
      self.object = responseObject
      self.error = error
    end

    def success?
      !failure?
    end

    def failure?
      !!error
    end

    def body
      if operation && operation.responseString
        operation.responseString
      end
    end
  end
end
```
assistant