code: def set_mode(compatibility=None):
      if compatibility:
          raise NotImplementedError(
              "Compatibility mode is only available in"
              " statsmodels <= 0.9"
          )
  
imports: import numpy
  from scipy.linalg import solve_sylvester
  import pandas
  from statsmodels.compat.pandas import Appender
  from statsmodels.tools.data import _is_using_pandas
  from scipy.linalg.blas import find_best_blas_type
  from .None import _initialization, _representation, _kalman_filter, _kalman_smoother, _simulation_smoother, _cfa_simulation_smoother, _tools
label_desc: Use image node_id 1 for calling a global function with example usage: set_mode(compatibility) without return types