code: def _check_zero_phase_length(N, phase, gain_nyq=0):
      N = int(N)
      if N % 2 == 0:
          if phase == "zero":
              raise RuntimeError(
                  f'filter_length must be odd if phase="zero", got {N}'
              )
          elif phase == "zero-double" and gain_nyq == 1:
              N += 1
      return N
  
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 9 for calling a global function with example usage: _check_zero_phase_length(N, phase, gain_nyq) and returns: N