title: Discord.py check define message.content
body: <p>I want to check when I use the command, which object I sent e.g. user/member, channel, role</p>
  <pre class="lang-py prettyprint-override"><code>@foo.command()
  async def define(ctx, arg) #the arg as id, mention or name
     if arg == discord.Role:
       await ctx.send(&quot;its a role&quot;)
     elif == discord.Channel:
       await ctx.send(&quot;its an channel&quot;)
      # more checks
  </code></pre>