anchor.diff:     * if types the last char of a valid option, hitting tab should complete it
      */
     if(!compLine.endsWith(' ') && parserOptionCompletions.contains(lastArg)) {
  -    _log('completing final arg');
  +    sublog('completing final arg');
       return [lastArg];
     }
   
  -  _log("so...uh...now what?");
  +  sublog("so...uh...now what?");
   
     return [];
   }
  
positive.code:   final validSubSet = subsetTuple.item1;
    final subsetResult = subsetTuple.item2;
  
    _log('valid subset: ${_helpfulToString(validSubSet)}');
  
    /*
     * CASE: we have a command
  
negative.code:     require(arg.trim() == arg, msg.concat('has whitespace'));
    }
  
    final sublog = (Object obj) {
      _log(obj, ['getArgsCompletions']);
    };
  
    sublog("provided args: ${_helpfulToString(providedArgs)}");
    sublog('COMP_LINE:  "$compLine"');
    sublog('COMP_POINT:  $compPoint');
  
  
    if(providedArgs.isEmpty) {
      sublog('empty args. Complete with all available commands');
      return parser.commands.keys.toList();
    }
  
  