docs: def node_done(self, ssid=None):
          """
          Release the servers for the specified ssid.
          The API doesn't provide any kind of output, try to be helpful by
          providing the list of servers to be released.
  
          :param ssid: ssid of the server pool
          :return: [ requested_hosts ]
          """
          if self.api_key is None:
              raise exceptions.ApiKeyRequired
  
          if ssid is None:
              raise exceptions.SsidRequired
  
          # There is no body replied in this call so at least get the hosts for
          # the specified ssid to return them.
          requested_hosts = dict()
          for host in self.self_inventory:
              if ssid == self.self_inventory[host]['comment']:
                  requested_hosts[host] = self.full_inventory[host]
  
          args = "key={key}&ssid={ssid}".format(key=self.api_key, ssid=ssid)
  
          resp, body = self.get('Node/done?%s' % args)
  
          return requested_hosts