_lookupNamespaceLoader(namespace) {
    /* eslint-disable no-restricted-syntax */
    for (const [key, value] of this.__namespacePatternsMap) {
      const isMatchingString = typeof key === 'string' && key === namespace;
      const isMatchingRegexp =
        typeof key === 'object' && key.constructor.name === 'RegExp' && key.test(namespace);
      if (isMatchingString || isMatchingRegexp) {
        return value;
      }
    }
    return null;
    /* eslint-enable no-restricted-syntax */
  }
@param {string} namespace
@returns {function|null}
@protected