code: public Guild getGuild()
      {
          TextChannel channel = getTextChannel();
          return channel != null ? channel.getGuild() : null;
      }
docs: The {@link net.dv8tion.jda.core.entities.Guild Guild} this Reaction was used in,
  this might return {@code null} when this Reaction was not used in a MessageChannel
  from the ChannelType {@link net.dv8tion.jda.core.entities.ChannelType#TEXT TEXT}!
  
  @return {@link net.dv8tion.jda.core.entities.Guild Guild} this Reaction was used in, or {@code null}