title: How do I make a bot respond to a specific reaction? Discord.py
body: <p>I am trying to add a giveaway function to my discord bot but the reroll function I am trying to make does not work. When the giveaway ends it sends a message that says who won the giveaway. This is what I have defined as reroll. Then I make the bot wait and see if someone has added a 'x' reaction to this message. I am trying to make it so that if someone has added an 'x' reaction then it will redo the winner choice in the giveaway. I hope to also make this function repeat if multiple winners are invalid. But I am not exactly sure how I would make a bot respond specifically to a specific reaction on a message.</p>
  <pre><code>reroll = await channel.send(f'Congratulations! {winner.mention} won {prize}!')
  
  if reroll.reactions == '❌':
  
      winner2 = random.choice(users)
  
      await channel.send(f'Congratulations! {winner2.mention} won {prize}!')
  </code></pre>