code: def format(self, node):
      params = self._default_function_params(node)
  
      lut_functions = {
          lut_fun.name: lut_fun.name
          for lut_fun in params["lut_functions"]
      }
      printer = HLSCodePrinter(
          node,
          lut_functions=lut_functions,
          use_built_in_luts=node.attributes["use_built_in_luts"],
      )
  
      fn_templates = []
      for i, expr in enumerate(node.attributes["expression"]):
          params["expr_str"] = printer.doprint(expr)
          params["y_index"] = str(i)
          fn_templates.append(self.template.format(**params))
  
      return fn_templates
  
imports: import re
  from sympy.core import S
  from sympy.core.numbers import Integer
  from sympy.printing.cxx import CXX11CodePrinter
  from hls4ml.backends.template import FunctionCallTemplate, LayerConfigTemplate
  from hls4ml.model.layers import SymbolicExpression
label_desc: Use image node_id 2 for calling the ExpressionFunctionTemplate obj's underlying member method code with example usage: obj.format(node) and returns: fn_templates