docs: def get_nonce_timestamp(nonce):
      '''
      Extract the timestamp from a Nonce. To be sure the timestamp was generated by this site,
      make sure you validate the nonce using validate_nonce().
      '''
      components = nonce.split(':',2)
      if not len(components) == 3:
          return None
  
      try:
          return float(components[0])
      except ValueError:
          return None