code: def getUrl(self):
      return self.getOrDefault(self.url)
  
imports: import json
  from os import error
  from langchain.chains.loading import load_chain_from_config
  from pyspark import keyword_only
  from pyspark.ml import Transformer
  from pyspark.ml.param.shared import HasInputCol, HasOutputCol, Param
  from pyspark.ml.util import DefaultParamsReadable, DefaultParamsWritable, DefaultParamsReader, DefaultParamsWriter
  from pyspark.sql.functions import udf, col
  from pyspark.sql.types import StructType, StructField, StringType
  from typing import cast, Optional, TypeVar, Type
  from synapse.ml.core.platform import running_on_synapse_internal
label_desc: Use image node_id 8 for calling the LangchainTransformer obj's underlying member method code with example usage: obj.getUrl() and returns: self