def _evaluate_priority_nil
      # Need to specify value explicitly here, otherwise in the call to
      # _evaluate_priority, the case statement won't recognize it as a Symbol.
      # That's because when calls Symbol::=== to evaluate a match.
      priority = config.default_priority

      if priority
        _evaluate_priority(priority)
      else
        raise Errors::InvalidPriorityError, priority.inspect
      end
    end
def _evaluate_priority_nil
      # Need to specify value explicitly here, otherwise in the call to
      # _evaluate_priority, the case statement won't recognize it as a Symbol.
      # That's because when calls Symbol::=== to evaluate a match.
      priority = config.default_priority

      if priority
        _evaluate_priority(priority)
      else
        raise Errors::InvalidPriorityError, priority.inspect
      end
    end
Evaluate nil as a priority.