title: Discord.py - Allow command in specific channel
body: <p>i need to use my discord command in specific channel , I'm using @client.command()
  I mean if i used my command in another channel will be not working</p>
  <pre><code>@client.command()
  async def w(ctx):
      channel = client.get_channel(775491463940669480)
  
      await ctx.send(&quot;hello) ```
  
   
  </code></pre>