code: def _visit_op(self, op):
      input_vars = _get_input_vars(op)
      for var in input_vars:
          assert (
              var in self.var_to_hypothetical_value
          ), "transpose optimization pass: hypothetical value for var '{}', not found".format(
              var.name
          )
  
      if op in self.output_sink_ops:
          self._visit_materialize_op(op)
      elif op.op_type in UNARY_LIKE_OP_TYPES:
          self._visit_unary_like_op(op)
      elif op.op_type in AXIS_UPDATE_OPS:
          self._visit_axis_update_op(op)
      elif op.op_type == "transpose":
          self._visit_transpose_op(op)
      elif op.op_type == "const":
          self.var_to_hypothetical_value[
              op.outputs[0]
          ] = HypotheticalValue(op.outputs[0])
      else:
          self._visit_materialize_op(op)
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  from coremltools.converters.mil.mil.passes.pass_registry import register_pass
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil.var import Var
  import logging
  import numpy
  import copy
  from collections import defaultdict
label_desc: Use image node_id 7 for calling the TransposeOptimization obj's underlying member method code with example usage: obj._visit_op(op) without return types