code: def _fread3(fobj):
      """Read a 3-byte int from an open binary file object
  
      Parameters
      ----------
      fobj : file
          File descriptor
  
      Returns
      -------
      n : int
          A 3 byte int
      """
      b1, b2, b3 = np.fromfile(fobj, ">u1", 3).astype(np.int64)
      return (b1 << 16) + (b2 << 8) + b3
  
file_path: nibabel/nibabel/freesurfer/io.py
imports: import getpass
  import time
  import warnings
  from collections import OrderedDict
  import numpy
  from ..openers import Opener
label_desc: Use image node_id 1 for calling a global function with example usage: _fread3(fobj) and returns: unknown