code: function handleErrorPerErrorCode(error, exemptedCodes, callback) {
  	if (exemptedCodes.indexOf(error.code) === -1) {
  		return callback(error);
  	} else {
  		return setTimeout(callback, READY_RETRY_INTERVAL);
  	}
  }
docs: This function will:
  
  1. Call the callback function with the error as the first argument, or;
  2. Simply call the callback if the code is exempted.
  
  This is generally going to be used as part of an `async.whilst` call chain,
  and will either trigger a hard failure if the error code is not ignored, or
  a retry if it is.
  
  @summary Handle an error depending on the error code
  @param {Error} error - The received error code
  @param {Array} exemptedCodes - Codes for which we should retry
  @param {Function} callback - The callback function to trigger in both cases