class_docstr: A visitor to traverse subgraphs and build Core ML models.
code: def visit_call(self, call):
      inputs = []
      for arg in call.args:
          super().visit(arg)
          for out in self.out_map[arg]:
              inputs.append(out)
      outputs = ["buf_" + str(self.buf_idx_)]
      op_name = call.op.name
      layer_name = op_name + "_" + str(self.buf_idx_)
  
      assert op_name in _convert_map, f"{op_name} is not supported"
      _convert_map[op_name](
          self.builder,
          layer_name,
          inputs,
          outputs,
          call.args,
          call.attrs,
      )
  
      self.buf_idx_ = self.buf_idx_ + 1
      self.out_map[call] = outputs
  
imports: import os
  import shutil
  import tvm._ffi
  from ...relay.expr_functor import ExprVisitor
  from ..None import xcode, coreml_runtime
label_desc: Use image node_id 4 for calling the CodegenCoreML obj's underlying member method code with example usage: obj.visit_call(call) without return types