code: def accounts_frontiers(self, accounts):
          
  
          accounts = self._process_value(accounts, 'list')
  
          payload = {"accounts": accounts}
  
          resp = self.call('accounts_frontiers', payload)
  
          return resp.get('frontiers') or {}
docs: Returns a list of pairs of account and block hash representing the
          head block for **accounts** list
  
          :param accounts: Accounts to return frontier blocks for
          :type accounts: list of str
  
          :raises: :py:exc:`nano.rpc.RPCException`
  
          >>> rpc.accounts_frontiers(
          ...     accounts=[
          ...         "xrb_3t6k35gi95xu6tergt6p69ck76ogmitsa8mnijtpxm9fkcm736xtoncuohr3",
          ...         "xrb_3i1aq1cchnmbn9x5rsbap8b15akfh7wj7pwskuzi7ahz8oq6cobd99d4r3b7"
          ...     ]
          ... )
          {
              "xrb_3t6k35gi95xu6tergt6p69ck76ogmitsa8mnijtpxm9fkcm736xtoncuohr3":
                  "791AF413173EEE674A6FCF633B5DFC0F3C33F397F0DA08E987D9E0741D40D81A",
              "xrb_3i1aq1cchnmbn9x5rsbap8b15akfh7wj7pwskuzi7ahz8oq6cobd99d4r3b7":
                  "6A32397F4E95AF025DE29D9BF1ACE864D5404362258E06489FABDBA9DCCC046F"
          }