docs: function regexpForFunctionCall(fnName, args) {
    const optionalWhitespace = '\\s*';
    const argumentParts = args.map(
      arg => optionalWhitespace + arg + optionalWhitespace
    );
    let parts = [fnName, '\\(', argumentParts.join(','), '\\)'];
    return new RegExp(parts.join(''), 'g');
  }