code: def _compare_truncated_forecasts(full, trunc, start):
      assert np.all(np.isfinite(trunc.forecasts[:start]))
      assert_allclose(trunc.forecasts, full.forecasts[start:])
  
      if full.forecast_paths is None:
          assert trunc.forecast_paths is None
          assert trunc.shocks is None
          return
  
imports: import numpy
  from numpy.random import RandomState
  from numpy.testing import assert_allclose
  import pandas
  import pytest
  from arch.univariate import arch_model
  from arch.univariate.distribution import Normal, StudentsT
  from arch.univariate.mean import ConstantMean
  from arch.univariate.volatility import APARCH, EGARCH, FIGARCH, GARCH, HARCH, BootstrapRng, ConstantVariance, EWMAVariance, FixedVariance, MIDASHyperbolic, RiskMetrics2006
label_desc: Use image node_id 1 for calling a global function with example usage: _compare_truncated_forecasts(full, trunc, start) without return types