class_docstr: Subset columns
  
  Parameters
  ----------
  names
      List of columns to keep
class_docstr_tok: ["Subset","columns","Parameters","--","--","--","--","--","names","List","of","columns","to","keep"]
code: def transform_summary(self, to_keep):
      return "Keeping {:,} column(s)".format(len(to_keep))
  
imports: from copy import copy, deepcopy
  import abc
  import inspect
  import importlib
  import itertools
  from collections.abc import Mapping
  import pandas
  from decorator import decorator
  from sklearn_evaluation.exceptions import DataSelectorError
  from sklearn_evaluation.util import map_parameters_in_fn_call
  from sklearn_evaluation.table import Table
label_desc: Use image node_id 3 for calling the ColumnKeep obj's underlying member method code with example usage: obj.transform_summary(to_keep) and returns: str