docstr: Function to set the bitmap and specify the function to unload it.
code: def _set_bitmap(self, bitmap, close_func=None):
      """Function to set the bitmap and specify the function to unload it."""
      if self._bitmap is not None:
          pass  # bitmap is converted
      if close_func is None:
          close_func = self._fi.lib.FreeImage_Unload, bitmap
  
      self._bitmap = bitmap
      if close_func:
          self._close_funcs.append(close_func)
  
imports: import os
  import sys
  import ctypes
  import threading
  import logging
  import numpy
  from ..core import get_remote_file, load_lib, Dict, resource_dirs, IS_PYPY, get_platform, InternetNotAllowedError, NeedDownloadError
label_desc: Use image node_id 4 for calling the FIBaseBitmap obj's underlying member method code with example usage: obj._set_bitmap(bitmap, close_func) without return types