private function fixAssertNegative(Tokens $tokens, $index, $method)
    {
        static $map = [
            'false' => 'assertNotFalse',
            'null' => 'assertNotNull',
            'true' => 'assertNotTrue',
        ];

        return $this->fixAssert($map, $tokens, $index, $method);
    }
private function fixAssertNegative(Tokens $tokens, $index, $method)
    {
        static $map = [
            'false' => 'assertNotFalse',
            'null' => 'assertNotNull',
            'true' => 'assertNotTrue',
        ];

        return $this->fixAssert($map, $tokens, $index, $method);
    }
@param Tokens $tokens
@param int    $index
@param string $method

@return null|int