docstr: get all index nodes in Milvus deployment
docstr_tok: ["get","all","index","nodes","in","Milvus","deployment"]
code: def index_nodes(self):
      """get all index nodes in Milvus deployment"""
      index_nodes = []
      for node in self.nodes:
          if "indexnode" == node.get("infos").get("type"):
              index_nodes.append(node)
      return index_nodes
  
file_path: milvus/tests/python_client/common/milvus_sys.py
imports: import ujson
  import json
  from pymilvus.grpc_gen import milvus_pb2
  from pymilvus import connections
label_desc: Use image node_id 8 for calling the MilvusSys obj's underlying member method code with example usage: obj.index_nodes() and returns: index_nodes