src/Service/TrackService.php
public function getSimilar(SimilarTrackBuilder $builder): array
    {
        $response = $this->client->unsignedCall('track.getSimilar', $builder->getQuery());

        if (!isset($response['similartracks']['track'])) {
            return [];
        }

        return ApiHelper::mapList(
            static function ($data) {
                return SongInfo::fromApi($data);
            },
            $response['similartracks']['track']
        );
    }
public function getSimilar(SimilarTrackBuilder $builder): array
    {
        $response = $this->client->unsignedCall('track.getSimilar', $builder->getQuery());

        if (!isset($response['similartracks']['track'])) {
            return [];
        }

        return ApiHelper::mapList(
            static function ($data) {
                return SongInfo::fromApi($data);
            },
            $response['similartracks']['track']
        );
    }
{@inheritdoc}