docstr: Makes a new connection attempt, caching the new namenode index and HDFS connection. 
code: def _do_connect(self):
      """Makes a new connection attempt, caching the new namenode index and HDFS connection."""
      (
          self._index_of_nn,
          self._hdfs,
      ) = self._connector_cls._try_next_namenode(
          self._index_of_nn, self._list_of_namenodes, user=self._user
      )
  
imports: import functools
  import inspect
  import logging
  import os
  from distutils.version import LooseVersion
  from xml.etree import ElementTree
  import pyarrow
  import six
  from pyarrow.hdfs import HadoopFileSystem
  from pyarrow.lib import ArrowIOError
  from six.moves.urllib.parse import urlparse
label_desc: Use image node_id 3 for calling the HAHdfsClient obj's underlying member method code with example usage: obj._do_connect() without return types