code: function(c, type, level) {
      if (c.values === undefined || c.values === null) return true;
  
      var failed = 0;
  
      // Value iterator function. Gets the value and index as arguments.
      // Collects boolean results.
      var viter = function(v, i) {
        if (v === undefined || v === null) return;
        failed += !iterator.call(context, v, type, level, i);
      };
  
      c.values.forEach(viter);
  
      return failed === 0;
    }
docs: Component iterator function. Gets the component, type (dimension|attribute), level (dataset|series|observation) as arguments