code: def _read_elc(fname, head_size):
      """Read .elc files.
  
      Parameters
      ----------
      fname : str
          File extension is expected to be '.elc'.
      head_size : float | None
          The size of the head in [m]. If none, returns the values read from the
          file with no modification.
  
      Returns
      -------
      montage : instance of DigMontage
          The montage in [m].
      """
      fid_names = ("Nz", "LPA", "RPA")
  
      ch_names_, pos = [], []
      with open(fname) as fid:
          # _read_elc does require to detect the units. (see _mgh_or_standard)
          for line in fid:
              if "UnitPosition" in line:
                  units = line.split()[1]
                  scale = dict(m=1.0, mm=1e-3)[units]
                  break
          else:
              raise RuntimeError(
                  "Could not detect units in file %s" % fname
              )
          for line in fid:
              if "Positions\n" in line:
                  break
          pos = []
          for line in fid:
              if "Labels\n" in line:
                  break
              pos.append(list(map(float, line.split())))
          for line in fid:
              if not line or not set(line) - {" "}:
                  break
              ch_names_.append(line.strip(" ").strip("\n"))
  
      pos = np.array(pos) * scale
      if head_size is not None:
          pos *= head_size / np.median(np.linalg.norm(pos, axis=1))
  
      ch_pos = _check_dupes_odict(ch_names_, pos)
      nasion, lpa, rpa = (ch_pos.pop(n, None) for n in fid_names)
  
      return make_dig_montage(
          ch_pos=ch_pos,
          coord_frame="unknown",
          nasion=nasion,
          lpa=lpa,
          rpa=rpa,
      )
  
imports: import csv
  import os.path
  from collections import OrderedDict
  from functools import partial
  import numpy
  from .._freesurfer import get_mni_fiducials
  from ..transforms import _sph_to_cart
  from ..utils import _pl, _soft_import, warn
  from .None import __file__
  from .montage import make_dig_montage
label_desc: Use image node_id 11 for calling a global function with example usage: _read_elc(fname, head_size) and returns: make_dig_montage