code: def _get_workflow_by_name(workflow_name, user_uuid):
      
      from reana_db.models import Workflow
      workflow = Workflow.query.filter(
          Workflow.name == workflow_name,
          Workflow.owner_id == user_uuid). \
          order_by(Workflow.run_number.desc()).first()
      if not workflow:
          raise ValueError(
              'REANA_WORKON is set to {0}, but '
              'that workflow does not exist. '
              'Please set your REANA_WORKON environment '
              'variable appropriately.'.
              format(workflow_name))
      return workflow
docs: From Workflows named as `workflow_name` the latest run_number.
  
      Only use when you are sure that workflow_name is not UUIDv4.
  
      :rtype: reana-db.models.Workflow