The only issue I can see here is the fact that 404 can be returned in 2 instances: 
1. The user is not a collaborator. 
2. The user does not exist.

The only way to tell these apart is through the error message Github returns. ```parseBoolResponse()``` will not return the error on a 404, so we would have no way of determining the reason of failure. Do we care about making a distinction between the two?