class_docstr: Transformer that performs identity operation, f(x)=x.
class_docstr_tok: ["Transformer","that","performs","identity","operation",",","f","(","x",")","=x","."]
code: def persist(self, filepath):
      logger.info('"IdentityOperation" is not persistable.')
      pass
  
imports: import os
  import pprint
  from collections import defaultdict
  from sklearn.externals import joblib
  from steppy.adapter import Adapter, AdapterError
  from steppy.utils import display_upstream_structure, persist_as_png, get_logger, initialize_logger
label_desc: Use image node_id 2 for calling the IdentityOperation obj's underlying member method code with example usage: obj.persist(filepath) without return types