code: def stftfreq(wsize, sfreq=None):  # noqa: D401
      """Compute frequencies of stft transformation.
  
      Parameters
      ----------
      wsize : int
          Size of stft window.
      sfreq : float
          Sampling frequency. If None the frequencies are given between 0 and pi
          otherwise it's given in Hz.
  
      Returns
      -------
      freqs : array
          The positive frequencies returned by stft.
  
      See Also
      --------
      stft
      istft
      """
      freqs = rfftfreq(wsize)
      if sfreq is not None:
          freqs *= float(sfreq)
      return freqs
  
file_path: mne-python/mne/time_frequency/_stft.py
imports: from math import ceil
  import numpy
  from scipy.fft import irfft, rfft, rfftfreq
  from ..utils import logger, verbose
label_desc: Use image node_id 3 for calling a global function with example usage: stftfreq(wsize, sfreq) and returns: freqs