docs: def update_nanopubstore_start_dt(url: str, start_dt: str):
      """Add nanopubstore start_dt to belapi.state_mgmt collection
  
      Args:
          url: url of nanopubstore
          start_dt: datetime of last query against nanopubstore for new ID's
      """
  
      hostname = urllib.parse.urlsplit(url)[1]
  
      start_dates_doc = state_mgmt.get(start_dates_doc_key)
      if not start_dates_doc:
          start_dates_doc = {
              "_key": start_dates_doc_key,
              "start_dates": [{"nanopubstore": hostname, "start_dt": start_dt}],
          }
          state_mgmt.insert(start_dates_doc)
      else:
          for idx, start_date in enumerate(start_dates_doc["start_dates"]):
              if start_date["nanopubstore"] == hostname:
                  start_dates_doc["start_dates"][idx]["start_dt"] = start_dt
                  break
          else:
              start_dates_doc["start_dates"].append(
                  {"nanopubstore": hostname, "start_dt": start_dt}
              )
  
          state_mgmt.replace(start_dates_doc)