In the Lightning Now event I just attended, I recall hearing about the following error when trying to complete the "Use a Visualforce Page as a Component in a Lightning Page" module, but can't remember how to fix this.

    Challenge Not yet complete... here's what's wrong: 

    Could not find a method named 'getIsClassic' in 'GetPropertiesApexController'. Check your code and      try again.

Could someone please remind me how to fix this?