code: def boot_time():
      """The system boot time expressed in seconds since the epoch."""
      return cext.boot_time()
  
imports: import contextlib
  import errno
  import functools
  import os
  from collections import namedtuple
  from .None import _common
  from .None import _psposix
  from .None import _psutil_osx
  from .None import _psutil_posix
  from ._common import AccessDenied
  from ._common import conn_tmap
  from ._common import conn_to_ntuple
  from ._common import isfile_strict
  from ._common import memoize_when_activated
  from ._common import NoSuchProcess
  from ._common import parse_environ_block
  from ._common import usage_percent
  from ._common import ZombieProcess
  from ._compat import PermissionError
  from ._compat import ProcessLookupError
label_desc: Use image node_id 13 for calling a global function with example usage: boot_time() and returns: cext