Check if theme exists

@param string $key
@return bool
551349
public function has(?string $key) : bool
    {
        return $key === null ? false : isset($this->themes[$key]);
    }
24812
public function exists($key)
    {
        $path = $this->computePath($key);

        return $this->fileSystem->exists($path);
    }
636374
public function has($key)
    {
        return (isset($this->headers[$this->normalizeKey($key)])) ? true : false;
    }
763943
public function has(string $key): bool
    {
        $result = $this->iterateConfig($key);

        return !($result === null);
    }
52022
public function has($key)
    {
        $parts     = $this->getPath($key);
        $keyExists = true;
        $node      = $this->getFromCache();

        foreach($parts as $part) {
            $part = trim($part);

            if (!is_array($node) || !array_key_exists($part, $node)) {
                $keyExists = false;
                break;
            }

            $node = &$node[$part];
        }

        return ($keyExists);
    }
1029588
protected function exists($key)
    {
        if ($this->enabled && opcache_is_script_cached($this->filePath($key))) {
            return true;
        }
        return file_exists($this->filePath($key));
    }
633623
public function hasFileIcon(string $key): bool
    {
        return $this->file_icons instanceof Collection && $this->file_icons->has($key);
    }
1088173
public function has($key)
    {
        $keys = (func_num_args() > 1) ? func_get_args() : (array) $key;

        foreach ($keys as $key) {
            if(!array_key_exists($key, $_SESSION))
                return false;
        }

        return true;
    }
770565
public function exists( $key ) {
		return ! collect( is_array( $key ) ? $key : func_get_args() )->contains(
			function ( $key ) {
				return ! Arr::exists( $this->attributes, $key );
			}
		);
	}
433328
public function has(string $key): bool
    {
        $key = $this->prepareKey($key);
        return Arr::has($this->properties, $key);
    }
1239417
public function has($key)
    {
        if (!$this->isEnabled()) {
            return false;
        }

        return (false !== apc_fetch($this->prefix() . $key));
    }
278793
public function has($key)
	{
		$key = $this->id($key);
		return $this->apcu ? apcu_exists($key) : apc_exists($key);
	}
1086491
public function has($key)
    {
        $key = trim($key, '.');
        if (strpos($key, '.') !== false) {
            $array =& $this->_items;
            foreach (explode('.', $key) as $v) {
                if (!isset($array[$v]))
                    return false;
                else
                    $array =& $array[$v];
            }
            return true;
        } else {
            return array_key_exists($key, $this->_items);
        }
    }
5909
public function exists($key)
    {
        $placeholder = new stdClass;

        return ! collect(is_array($key) ? $key : func_get_args())->contains(function ($key) use ($placeholder) {
            return $this->get($key, $placeholder) === $placeholder;
        });
    }
727280
public function has(string $key): bool
    {
        return isset($this->data[$key]) || array_key_exists($key, $this->data);
    }
21708
public function hasConfig(string $key)
    {
        $redis = $this->getDI()->getRedis();
        $hashKey = $this->getNotificationKey(); //'user_notifications_'.$this->user_id;

        return $redis->hGet($hashKey, $key);
    }
600603
public function has($key)
    {
        if (array_key_exists($key, $this->settings)) {
            return true;
        }

        return $this->fallback instanceof Config
            ? $this->fallback->has($key)
            : false;
    }