code: def transform(self, ctx: Context, transform_data):
      logger.debug(f"Start transform")
      drop_cols = set(self._selected_mask[~self._selected_mask].index)
      cols = transform_data.schema.columns.to_list()
      select_cols = [col for col in cols if col not in drop_cols]
      return transform_data[select_cols]
  
imports: import copy
  import logging
  import math
  import random
  import numpy
  import pandas
  from fate.arch import Context
  from ..abc.module import HeteroModule, Module
label_desc: Use image node_id 16 for calling the StandardSelection obj's underlying member method code with example usage: obj.transform(ctx, transform_data) and returns: transform_data