get system boot time in milliseconds in python

main.py
import datetime
import os

boot_time_timestamp = os.path.getmtime('/proc/stat')
boot_time = datetime.datetime.fromtimestamp(boot_time_timestamp)

uptime = datetime.datetime.now() - boot_time
milliseconds_since_boot = int(uptime.total_seconds() * 1000)

print(milliseconds_since_boot)
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