code: def _assign_causal_mechanisms(causal_model):
      causal_model.set_causal_mechanism("X0", EmpiricalDistribution())
      causal_model.set_causal_mechanism(
          "X1",
          AdditiveNoiseModel(
              create_linear_regressor_with_given_parameters(
                  coefficients=np.array([2])
              )
          ),
      )
      causal_model.set_causal_mechanism(
          "X2",
          AdditiveNoiseModel(
              create_linear_regressor_with_given_parameters(
                  coefficients=np.array([0.5])
              )
          ),
      )
      causal_model.set_causal_mechanism(
          "X3",
          AdditiveNoiseModel(
              create_linear_regressor_with_given_parameters(
                  coefficients=np.array([0.5])
              )
          ),
      )
  
file_path: dowhy/tests/gcm/test_equation_parser.py
imports: import networkx
  import numpy
  import pandas
  from flaky import flaky
  from dowhy.gcm import AdditiveNoiseModel, EmpiricalDistribution, ProbabilisticCausalModel, create_causal_model_from_equations, fit
  from dowhy.gcm.causal_mechanisms import ConditionalStochasticModel
  from dowhy.gcm.ml import create_linear_regressor_with_given_parameters
label_desc: Use image node_id 7 for calling a global function with example usage: _assign_causal_mechanisms(causal_model) without return types