code: def _maybe_sqr_transform(self, expr):
      if "sqrt" in self.objective_config_parts:
          expr = ast.IdExpr(expr, to_reuse=True)
          return utils.mul(ast.AbsExpr(expr), expr)
      else:
          return expr
  
imports: import json
  import math
  import numpy
  from m2cgen import ast
  from m2cgen.assemblers import utils
  from m2cgen.assemblers.base import ModelAssembler
  from m2cgen.assemblers.linear import _linear_to_ast
label_desc: Use image node_id 9 for calling the LightGBMModelAssembler obj's underlying member method code with example usage: obj._maybe_sqr_transform(expr) and returns: utils, expr