```js
// index.js
// ...
import { Player } from 'discord-player';
import pkg from '@discord-player/extractor';  // I
const { YouTubeExtractor, SpotifyExtractor, SoundcloudExtractor, AppleMusicExtractor } = pkg;  // Extract relevant extractors

// ...
const player = new Player(client)
player.extractors.register(YouTubeExtractor);
player.extractors.register(SpotifyExtractor);
player.extractors.register(SoundcloudExtractor);
player.extractors.register(AppleMusicExtractor);

global.player = player
// ...
```

```js
// play.js

import { SlashCommandBuilder } from 'discord.js';

export default {
    data: new SlashCommandBuilder()
        .setName('play')
        .setDescription('Play music from a YouTube URL or search term')
        .addStringOption(option =>
            option.setName('query')
                .setDescription('The YouTube URL or search term to play')
                .setRequired(true)
        ),

    async execute(interaction) {
        const query = interaction.options.getString('query');
        const channel = interaction.member.voice.channel;

        if (!channel) {
            return interaction.reply('You need to join a voice channel first!');
        }

        // Ensure the query is a valid string
        if (typeof query !== 'string' || !query.trim()) {
            return interaction.reply('Please provide a valid search query or URL.');
        }

        try {
            // Search for the track using the provided query
            const result = await player.search(query, {
                requestedBy: interaction.user,
                searchEngine: 'ytsearch'
            });

            // If no results are found, inform the user
            if (result.tracks.length === 0) {
                return interaction.reply('No results found for the given query!');
            }

            // Create a queue for the voice channel
            const queue = player.nodes.create(interaction.guild, {
                metadata: {
                    channel: interaction.channel,
                },
            });

            // Connect to the voice channel if not already connected
            if (!queue.connection) {
                await queue.connect(channel);
            }

            // Add the first track to the queue
            queue.addTrack(result.tracks[0]);

            // Start playing the track if the bot isn't already playing
            if (!queue.isPlaying()) {
                await queue.play();
            }

            // Inform the user about the track being played
            return interaction.reply(`Now playing **${result.tracks[0].title}**`);
        } catch (error) {
            console.error('Error during play command execution:', error);
            return interaction.reply('An error occurred while trying to play the track.');
        }
    }
};
```