code: def _register_flows(self):
      vivado_types = [
          "vivado:transform_types",
      ]
      vivado_types_flow = register_flow(
          "specific_types",
          vivado_types,
          requires=None,
          backend=self.name,
      )
  
      validation_passes = [
          "symbolicexpression:validate_user_lookup_table",
      ]
      validation_flow = register_flow(
          "validation",
          validation_passes,
          requires=None,
          backend=self.name,
      )
  
      template_flow = register_flow(
          "apply_templates",
          self._get_layer_templates,
          requires=None,
          backend=self.name,
      )
  
      writer_passes = ["make_stamp", "symbolicexpression:write_hls"]
      self._writer_flow = register_flow(
          "write",
          writer_passes,
          requires=["vivado:ip"],
          backend=self.name,
      )
  
      ip_flow_requirements = [
          vivado_types_flow,
          validation_flow,
          template_flow,
      ]
      ip_flow_requirements = list(filter(None, ip_flow_requirements))
  
      self._default_flow = register_flow(
          "ip", None, requires=ip_flow_requirements, backend=self.name
      )
  
file_path: hls4ml/hls4ml/backends/symbolic/symbolic_backend.py
imports: import os
  import sys
  from hls4ml.backends import FPGABackend
  from hls4ml.model.flow import register_flow
  from hls4ml.report import parse_vivado_report
label_desc: Use image node_id 2 for calling the SymbolicExpressionBackend obj's underlying member method code with example usage: obj._register_flows() without return types