code: def checkout(lancet, force, issue):
      
      issue = get_issue(lancet, issue)
  
      # Get the working branch
      branch = get_branch(lancet, issue, create=force)
  
      with taskstatus("Checking out working branch") as ts:
          if not branch:
              ts.abort("Working branch not found")
          lancet.repo.checkout(branch.name)
          ts.ok('Checked out "{}"', branch.name)
docs: Checkout the branch for the given issue.
  
      It is an error if the branch does no exist yet.