code: def fiff_open(fname, preload=False, verbose=None):
      """Open a FIF file.
  
      Parameters
      ----------
      fname : path-like | fid
          Name of the fif file, or an opened file (will seek back to 0).
      preload : bool
          If True, all data from the file is read into a memory buffer. This
          requires more memory, but can be faster for I/O operations that require
          frequent seeks.
      %(verbose)s
  
      Returns
      -------
      fid : file
          The file descriptor of the open file.
      tree : fif tree
          The tree is a complex structure filled with dictionaries,
          lists and tags.
      directory : list
          A list of tags.
      """
      fid = _fiff_get_fid(fname)
      try:
          return _fiff_open(fname, fid, preload)
      except Exception:
          fid.close()
          raise
  
imports: import os.path
  from gzip import GzipFile
  from io import SEEK_SET, BytesIO
  import numpy
  from scipy.sparse import issparse
  from ..utils import _file_like, logger, verbose, warn
  from .constants import FIFF
  from .tag import Tag, _call_dict_names, _matrix_info, _read_tag_header, read_tag
  from .tree import dir_tree_find, make_dir_tree
label_desc: Use image node_id 3 for calling a global function with example usage: fiff_open(fname, preload, verbose) and returns: _fiff_open