code: def _assign_causal_mechanisms(causal_model):
      causal_model.set_causal_mechanism("X0", EmpiricalDistribution())
      causal_model.set_causal_mechanism(
          "X1", AdditiveNoiseModel(create_linear_regressor())
      )
      causal_model.set_causal_mechanism(
          "X2", AdditiveNoiseModel(create_linear_regressor())
      )
      causal_model.set_causal_mechanism(
          "X3", AdditiveNoiseModel(create_linear_regressor())
      )
  
imports: import networkx
  import numpy
  import pandas
  from flaky import flaky
  from pytest import approx
  from dowhy.gcm import AdditiveNoiseModel, EmpiricalDistribution, ProbabilisticCausalModel, distribution_change, distribution_change_of_graphs, fit
  from dowhy.gcm.auto import AssignmentQuality
  from dowhy.gcm.distribution_change import mechanism_change_test
  from dowhy.gcm.ml import create_linear_regressor
  from dowhy.gcm.shapley import ShapleyConfig
label_desc: Use image node_id 7 for calling a global function with example usage: _assign_causal_mechanisms(causal_model) without return types