docstr: Remove the last page from the freelist and return its page.
code: def _pop_from_freelist(self) -> Optional[int]:
      """Remove the last page from the freelist and return its page."""
      second_to_last_node, last_node = self._traverse_free_list()
  
      if last_node is None:
          # Freelist is completely empty, nothing to pop
          return None
  
      if second_to_last_node is None:
          # Write in metadata that the freelist is empty
          self._freelist_start_page = 0
          self.set_metadata(None, None)
      else:
          second_to_last_node.next_page = None
          self.set_node(second_to_last_node)
  
      return last_node.page
  
imports: import enum
  import io
  from logging import getLogger
  import os
  import platform
  from typing import Union, Tuple, Optional
  import cachetools
  import rwlock
  from .node import Node, FreelistNode
  from .const import ENDIAN, PAGE_REFERENCE_BYTES, OTHERS_BYTES, TreeConf, FRAME_TYPE_BYTES
label_desc: Use image node_id 11 for calling the FileMemory obj's underlying member method code with example usage: obj._pop_from_freelist() and returns: last_node, None