check = (section, accumulatedName) => {
        for (const key in section) {
          const name = (accumulatedName) ? (accumulatedName + '.' + key) : key;
          const value = section[key];

          if (!exceptions.has(name)) {
            if (configPrimitives.has(typeof value)) {
              checkValueNameFn(name);
            } else {
              // It's a sub-section.
              check(value, name);
            }
          }
        }
      }
@param {!Object} section
@param {string} accumulatedName