```ruby
class DiscourseSignOutWorker < DiscourseWorker
  include Sidekiq::Worker

  def perform(user_id)
    for_each_tenant(user_id) do |u,t|
      client(t) do |c|
        discourse_user = c.user(u.username)
        c.log_out(discourse_user['id'])
      end
    end
  rescue DiscourseApi::Error
    logger.warn "User with ID '#{user_id}' couldn't be signed out from discourse (does a discourse account exist?)"
  end
end
```

Fix NPE if user does not exist in discourse instance
user
```ruby
class DiscourseSignOutWorker < DiscourseWorker
  include Sidekiq::Worker

  def perform(user_id)
    for_each_tenant(user_id) do |u,t|
      client(t) do |c|
        discourse_user = c.user(u.username)
        c.log_out(discourse_user['id']) unless discourse_user.nil?
      end
    end
  rescue DiscourseApi::Error
    logger.warn "User with ID '#{user_id}' couldn't be signed out from discourse (does a discourse account exist?)"
  end
end
```
assistant