code: def __str__(self):
      s = "Realized estimand: {0}\n".format(self.estimator_name)
      s += "Realized estimand type: {0}\n".format(self.estimand_type)
      s += "Estimand expression:\n{0}\n".format(
          sp.pretty(self.estimand_expression)
      )
      j = 1
      for ass_name, ass_str in self.assumptions.items():
          s += "Estimand assumption {0}, {1}: {2}\n".format(
              j, ass_name, ass_str
          )
          j += 1
      return s
  
imports: import copy
  import logging
  from collections import namedtuple
  from typing import Dict, List, Optional, Union
  import numpy
  import pandas
  import sympy
  from sklearn.utils import resample
  import dowhy.interpreters
  from dowhy.causal_identifier.identified_estimand import IdentifiedEstimand
  from dowhy.utils.api import parse_state
label_desc: Use image node_id 4 for calling the RealizedEstimand obj's underlying member method code with example usage: obj.__str__() and returns: s