Getting Windows Last Boot Time in Python

last_boot.py

#!/usr/bin/env python3

import datetime
import os

# import wmi
# https://github.com/tjguk/wmi
# https://github.com/tcely/wmi

class LastBoot:
    _wmi_module = False

    def _make_datetime_windows(self):
        assert self._wmi_module, 'Install wmi using pip'
        self.utc_offset = None
        tzinfo = datetime.timezone.utc
        c = wmi.WMI(find_classes=False)
        for obj in c.Win32_OperatingSystem():
            last_boot = obj.LastBootUpTime
            tt = wmi.to_time(last_boot)
            utc_offset_str = last_boot[21:]
            try:
                utc_offset = int(utc_offset_str, 10)
            except (TypeError, ValueError):
                pass
            else:
                self.utc_offset = datetime.timedelta(minutes=utc_offset)
                tzinfo = datetime.timezone(self.utc_offset)

            return datetime.datetime(*tt[0:6], tzinfo=tzinfo)

    def _make_datetime(self):
        if 'nt' == os.name:
            return self._make_datetime_windows()
        return datetime.datetime.now()

    @property
    def datetime(self):
        self._datetime = self._make_datetime()
        return self._datetime

try:
    import wmi
except ModuleNotFoundError:
    pass
else:
    LastBoot._wmi_module = True

if '__main__' == __name__:
    last_boot_dt = LastBoot().datetime
    print( last_boot_dt.isoformat(timespec='seconds') )

testing_extras.py

class DummyObj():
    pass

class DummyC():
    def Win32_OperatingSystem(self):
        obj = DummyObj()
        obj.LastBootUpTime = '20250102123456.987654-120'
        return list((obj,))

class DummyWMI():
    def WMI(self, *args, **kwargs):
        return DummyC()