def clean_single(number, force = false)
      request = server.pull_request(source_repo, number)
      if request && request.state == 'closed'
        # ensure there are no unmerged commits or '--force' flag has been set
        branch_name = request.head.ref
        if unmerged_commits?(branch_name) && !force
          puts "Won't delete branches that contain unmerged commits."
          puts "Use '--force' to override."
        else
          delete_branch(branch_name)
        end
      end
    rescue Octokit::NotFound
      false
    end
def clean_single(number, force = false)
      request = server.pull_request(source_repo, number)
      if request && request.state == 'closed'
        # ensure there are no unmerged commits or '--force' flag has been set
        branch_name = request.head.ref
        if unmerged_commits?(branch_name) && !force
          puts "Won't delete branches that contain unmerged commits."
          puts "Use '--force' to override."
        else
          delete_branch(branch_name)
        end
      end
    rescue Octokit::NotFound
      false
    end
clean a single request's obsolete branch