code: function(set, role) {
  		var validForNodeType = function(implicitNodeTypeSelector) {
  			return axe.utils.matchesSelector(node, implicitNodeTypeSelector);
  		};
  
  		if (role.implicit && role.implicit.some(validForNodeType)) {
  			set.push(role.name);
  		}
  
  		return set;
  	}
docs: /*
  Filter function to reduce a list of roles to a valid list of roles for a nodetype