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    <h3>Editing: VersionComparisonOperator.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php declare(strict_types=1);
/*
 * This file is part of PHPUnit.
 *
 * (c) Sebastian Bergmann &lt;sebastian@phpunit.de&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace PHPUnit\Util;

use function in_array;
use function sprintf;

/**
 * @internal This class is not covered by the backward compatibility promise for PHPUnit
 *
 * @psalm-immutable
 */
final class VersionComparisonOperator
{
    /**
     * @psalm-var '&lt;'|'lt'|'&lt;='|'le'|'&gt;'|'gt'|'&gt;='|'ge'|'=='|'='|'eq'|'!='|'&lt;&gt;'|'ne'
     */
    private $operator;

    public function __construct(string $operator)
    {
        $this-&gt;ensureOperatorIsValid($operator);

        $this-&gt;operator = $operator;
    }

    /**
     * @return '!='|'&lt;'|'&lt;='|'&lt;&gt;'|'='|'=='|'&gt;'|'&gt;='|'eq'|'ge'|'gt'|'le'|'lt'|'ne'
     */
    public function asString(): string
    {
        return $this-&gt;operator;
    }

    /**
     * @throws Exception
     *
     * @psalm-assert '&lt;'|'lt'|'&lt;='|'le'|'&gt;'|'gt'|'&gt;='|'ge'|'=='|'='|'eq'|'!='|'&lt;&gt;'|'ne' $operator
     */
    private function ensureOperatorIsValid(string $operator): void
    {
        if (!in_array($operator, ['&lt;', 'lt', '&lt;=', 'le', '&gt;', 'gt', '&gt;=', 'ge', '==', '=', 'eq', '!=', '&lt;&gt;', 'ne'], true)) {
            throw new Exception(
                sprintf(
                    '&quot;%s&quot; is not a valid version_compare() operator',
                    $operator,
                ),
            );
        }
    }
}
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