processDeclarations method 
    
      
List
processDeclarations(
{ - bool checkBrace = true, 
}) 
    
    
  Implementation
  List<dynamic> processDeclarations({bool checkBrace = true}) {
  if (checkBrace) _eat(TokenKind.LBRACE);
  var declaration = CSSStyleDeclaration();
  List list = [declaration];
  do {
    var selectorGroup = _nestedSelector();
    while (selectorGroup != null) {
      // Nested selector so process as a ruleset.
      List<CSSRule> rule = processRule(selectorGroup)!;
      list.addAll(rule);
      selectorGroup = _nestedSelector();
    }
    processDeclaration(declaration);
  } while (_maybeEat(TokenKind.SEMICOLON));
  if (checkBrace) _eat(TokenKind.RBRACE);
  return list;
}