code: def call(self, action, params=None):
          
          params = params or {}
          params['action'] = action
  
          resp = self.session.post(self.host, json=params, timeout=self.timeout)
  
          result = resp.json()
  
          if 'error' in result:
              raise RPCException(result['error'])
  
          return result
docs: Makes an RPC call to the server and returns the json response
  
          :param action: RPC method to call
          :type action: str
  
          :param params: Dict of arguments to send with RPC call
          :type params: dict
  
          :raises: :py:exc:`nano.rpc.RPCException`
          :raises: :py:exc:`requests.exceptions.RequestException`
  
          >>> rpc.call(
          ...     action='account_balance',
          ...     params={
          ...         'account': 'xrb_3t6k35gi95xu6tergt6p69ck76ogmitsa8mnijtpxm9fkcm736xtoncuohr3'
          ...     })
          {'balance': '325586539664609129644855132177',
           'pending': '2309370940000000000000000000000000'}