title: discord.py purge command not working and no error
body: <p>So I want to purge the message of a particular member. This is my code.</p>
  <pre><code>@commands.command()
  async def purge_member(self, ctx, member: discord.Member):
      await ctx.channel.purge(limit=100, check=lambda message: message.author == member)
  </code></pre>
  <p>The problem is the messages of the member are not getting purged.
  It does not show any error either.</p>
  <p>I have tried many other methods instead of purge to delete but all of them refuse to work, with no errors</p>