code: def get_fc_date(out_config_file):
      
      if os.path.exists(out_config_file):
          with open(out_config_file) as in_handle:
              old_config = yaml.safe_load(in_handle)
              fc_date = old_config["fc_date"]
      else:
          fc_date = datetime.datetime.now().strftime("%y%m%d")
      return fc_date
docs: Retrieve flowcell date, reusing older dates if refreshing a present workflow.