You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sprint.rb
    path of file: ./repos/openproject/modules/backlogs/app/models
    
    the code of the file until where you have to start completion: #-- copyright
# OpenProject is an open source project management soft
    
  def activity
    bd = burndown('up')
    return false if bd.blank?

    # Assume a sprint is active if it's only 2 days old
    return true if bd.remaining_hours.size <= 2

    WorkPackage.exists?(['version_id = ? and ((updated_at between ? and ?) or (created_at between ? and ?))',
                         id, -2.days.from_now, Time.now, -2.days.from_now, Time.now])
  end