ReferenceError starting plugin 
My homebridge plugin has been working fine and today it suddenly started crashing on startup. I am seeing an error in the fan.js file (line 48). See the attached screenshot from the terminal:
![reference_error](https://user-images.githubusercontent.com/35815728/36079918-67cca194-0f3d-11e8-891d-74b41ee0ac30.jpg)
