code: def _check_coefficients(system):
      """Check for filter stability."""
      if isinstance(system, tuple):
          z, p, k = signal.tf2zpk(*system)
      else:  # sos
          z, p, k = signal.sos2zpk(system)
      if np.any(np.abs(p) > 1.0):
          raise RuntimeError(
              "Filter poles outside unit circle, filter will be "
              "unstable. Consider using different filter "
              "coefficients."
          )
  
imports: from collections import Counter
  from copy import deepcopy
  from functools import partial
  from math import gcd
  import numpy
  from scipy import fft, signal
  from scipy.stats import f
  from ._fiff.pick import _picks_to_idx
  from ._ola import _COLA
  from .cuda import _fft_multiply_repeated, _fft_resample, _setup_cuda_fft_multiply_repeated, _setup_cuda_fft_resample, _smart_pad
  from .parallel import parallel_func
  from .utils import _check_option, _check_preload, _ensure_int, _pl, _validate_type, logger, sum_squared, verbose, warn
label_desc: Use image node_id 10 for calling a global function with example usage: _check_coefficients(system) without return types