code: def get_nibabel_data():
      """Return path to nibabel-data or empty string if missing
  
      First use ``NIBABEL_DATA_DIR`` environment variable.
  
      If this variable is missing then look for data in directory below package
      directory.
      """
      nibabel_data = environ.get("NIBABEL_DATA_DIR")
      if nibabel_data is None:
          mod = __import__("nibabel")
          containing_path = dirname(dirname(realpath(mod.__file__)))
          nibabel_data = pjoin(containing_path, "nibabel-data")
      return nibabel_data if isdir(nibabel_data) else ""
  
imports: import unittest
  from os import environ, listdir
  from os.path import dirname, exists, isdir
  from os.path import join
  from os.path import realpath
label_desc: Use image node_id 1 for calling a global function with example usage: get_nibabel_data() and returns: unknown