thread 1: "[<Apple_Pie.ViewController 0x7feec4d07cc0> setValue:forUnderfinedKey:]: this class is not key value coding-compliant for the key Tree." code example

Example: uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key

//Go to this link :)
//https://stackoverflow.com/questions/38308329/swift-setvalueforundefinedkey-this-class-is-not-key-value-coding-compliant-f