protected function checkDuplicates($path, array $vars = array())
    {
        $packageType = substr($vars['type'], strlen('bitrix') + 1);
        $localDir = explode('/', $vars['bitrix_dir']);
        array_pop($localDir);
        $localDir[] = 'local';
        $localDir = implode('/', $localDir);

        $oldPath = str_replace(
            array('{$bitrix_dir}', '{$name}'),
            array($localDir, $vars['name']),
            $this->locations[$packageType]
        );

        if (in_array($oldPath, static::$checkedDuplicates)) {
            return;
        }

        if ($oldPath !== $path && file_exists($oldPath) && $this->io && $this->io->isInteractive()) {

            $this->io->writeError('    <error>Duplication of packages:</error>');
            $this->io->writeError('    <info>Package ' . $oldPath . ' will be called instead package ' . $path . '</info>');

            while (true) {
                switch ($this->io->ask('    <info>Delete ' . $oldPath . ' [y,n,?]?</info> ', '?')) {
                    case 'y':
                        $fs = new Filesystem();
                        $fs->removeDirectory($oldPath);
                        break 2;

                    case 'n':
                        break 2;

                    case '?':
                    default:
                        $this->io->writeError(array(
                            '    y - delete package ' . $oldPath . ' and to continue with the installation',
                            '    n - don\'t delete and to continue with the installation',
                        ));
                        $this->io->writeError('    ? - print help');
                        break;
                }
            }
        }

        static::$checkedDuplicates[] = $oldPath;
    }