code: def get_default_flow(self):
      return self._default_flow
  
imports: import os
  from contextlib import contextmanager
  import numpy
  from hls4ml.backends import FPGABackend
  from hls4ml.model.attributes import ConfigurableAttribute, TypeAttribute
  from hls4ml.model.flow import register_flow
  from hls4ml.model.layers import GRU, LSTM, Activation, Conv1D, Conv2D, Dense, Embedding, Layer, SimpleRNN, Softmax
  from hls4ml.model.optimizer import get_backend_passes, layer_optimizer
  from hls4ml.model.types import FixedPrecisionType, IntegerPrecisionType, NamedType
  from hls4ml.report import parse_quartus_report
label_desc: Use image node_id 4 for calling the QuartusBackend obj's underlying member method code with example usage: obj.get_default_flow() and returns: self