code: def load_config(self):
      try:
          with open("ppml-conf.yaml", "r") as stream:
              conf = yaml.safe_load(stream)
              if "privateKeyFilePath" in conf:
                  self.secure = True
                  with open(conf["privateKeyFilePath"], "rb") as f:
                      private_key = f.read()
                  with open(conf["certChainFilePath"], "rb") as f:
                      certificate_chain = f.read()
                  self.server_credentials = grpc.ssl_server_credentials(
                      ((private_key, certificate_chain),)
                  )
              if "serverPort" in conf:
                  self.port = conf["serverPort"]
              self.generate_conf(conf)
  
      except Exception as e:
          logging.warn(
              'Failed to load config file "ppml-conf.yaml", using default config'
          )
          self.generate_conf({})
  
file_path: BigDL/python/ppml/src/bigdl/ppml/fl/nn/fl_server.py
imports: from concurrent import futures
  import grpc
  from bigdl.ppml.fl import *
  from bigdl.ppml.fl.nn.nn_service import NNServiceImpl
  import yaml
  import click
  from bigdl.ppml.fl.psi.psi_service import PSIServiceImpl
  from bigdl.ppml.fl.nn.generated.nn_service_pb2_grpc import *
  from bigdl.ppml.fl.nn.generated.psi_service_pb2_grpc import *
label_desc: Use image node_id 6 for calling the FLServer obj's underlying member method code with example usage: obj.load_config() without return types