code: def source_detector_distances(info, picks=None):
      r"""Determine the distance between NIRS source and detectors.
  
      Parameters
      ----------
      %(info_not_none)s
      %(picks_all_data)s
  
      Returns
      -------
      dists : array of float
          Array containing distances in meters.
          Of shape equal to number of channels, or shape of picks if supplied.
      """
      return np.array(
          [
              np.linalg.norm(
                  np.diff(
                      info["chs"][pick]["loc"][3:9].reshape(2, 3),
                      axis=0,
                  )[0]
              )
              for pick in _picks_to_idx(info, picks, exclude=[])
          ],
          float,
      )
  
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 1 for calling a global function with example usage: source_detector_distances(info, picks) and returns: np