class CanvasSync::JobBatches::ChainBuilder

def get_sub_chain(sub_type)
  matching_jobs = find_matching_jobs(sub_type).to_a
  raise "Found multiple \"#{sub_type}\" jobs in the chain" if matching_jobs.count > 1
  return nil if matching_jobs.count == 0
  job = matching_jobs[0][0]
  job = self.class.new(job) unless job.is_a?(ChainBuilder)
  job
end