code: def _zc_stencil(
      x: np.ndarray, threshold: float, zero_pos: bool
  ) -> np.ndarray:
      """Stencil to compute zero crossings"""
      x0 = x[0]
      if -threshold <= x0 <= threshold:
          x0 = 0
  
      x1 = x[-1]
      if -threshold <= x1 <= threshold:
          x1 = 0
  
      if zero_pos:
          return np.signbit(x0) != np.signbit(x1)  # type: ignore
      else:
          return np.sign(x0) != np.sign(x1)
  
imports: from __future__ import annotations
  import os
  import pathlib
  import warnings
  import soundfile
  import audioread
  import numpy
  import scipy.signal
  import soxr
  import lazy_loader
  from numba import jit, stencil, guvectorize
  from .fft import get_fftlib
  from .convert import frames_to_samples, time_to_samples
  from .._cache import cache
  from ..None import util
  from ..util.exceptions import ParameterError
  from ..util.decorators import deprecated
  from ..util.deprecation import Deprecated, rename_kw
  from .._typing import _FloatLike_co, _IntLike_co, _SequenceLike
  from typing import Any, BinaryIO, Callable, Generator, Optional, Tuple, Union, List
  from numpy.typing import DTypeLike, ArrayLike
label_desc: Use image node_id 12 for calling a global function with example usage: _zc_stencil(x, threshold, zero_pos) and returns: unknown, unknown