code: def _optode_position(info, optode):
      """Find the position of an optode."""
      idx = [optode in a for a in info.ch_names].index(True)
  
      if "S" in optode:
          loc_idx = range(3, 6)
      elif "D" in optode:
          loc_idx = range(6, 9)
  
      return info["chs"][idx]["loc"][loc_idx]
  
file_path: mne-python/mne/preprocessing/nirs/nirs.py
imports: import re
  import numpy
  from ..._fiff.pick import _picks_to_idx, pick_types
  from ...utils import _check_option, _validate_type, fill_doc
label_desc: Use image node_id 10 for calling a global function with example usage: _optode_position(info, optode) and returns: info