code: def format(self, node):
      params = self._default_config_params(node)
  
      lut_defs = []
      for lut_fun in params["lut_functions"]:
          type_name = params["result_t"].name
          if lut_fun.math_func in [
              "sinpi",
              "cospi",
              "sin",
              "cos",
              "asin",
              "acos",
              "atan",
              "atan2",
          ]:
              # We have return type overrides for these functions
              namespace = "nnet::"
          else:
              namespace = "hls::"
          lut_def = (
              f"nnet::lookup_table<{type_name}, "
              f"{lut_fun.table_size}, "
              f"{namespace}"
              f"{lut_fun.math_func}> "
              f"{lut_fun.name}"
              f"({lut_fun.range_start}, "
              f"{lut_fun.range_end});"
          )
          lut_defs.append(lut_def)
  
      return "\n".join(lut_defs)
  
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 ExpressionConfigTemplate obj's underlying member method code with example usage: obj.format(node) and returns: str