class_docstr: Simple selector that subsets a DataFrame to the columns of interest
  This allows a Pipeline that applies different transformations to subsets of columns,
     and unions that result
code: def __init__(self, column_names):
      self.column_names = column_names
  
file_path: greykite/greykite/sklearn/transform/column_selector.py
imports: import pandas
  from sklearn.base import BaseEstimator
  from sklearn.base import TransformerMixin
label_desc: Use image node_id 1 to create a new ColumnSelector object from inherited base classes: BaseEstimator, TransformerMixin with example: obj = ColumnSelector(column_names)