Stackoverflow count warm/cold by 5 minute interval

interval_count.py

import datetime

with open("myfile.csv") as f:
	window_from = None
	window_to = None
	warm = cold = 0
	for line in f:
		milliseconds, topics = line.split(",")
		if milliseconds == 'milliseconds':
			continue
		seconds = float(milliseconds) / 1000
		t1Convert = datetime.datetime.fromtimestamp(seconds)
		if window_from is None:
			window_from = t1Convert
			window_to = t1Convert + datetime.timedelta(minutes=5)
		if t1Convert > window_to:
			print("{} - {}: {} warm, {} cold".format(window_from, window_to, warm, cold))
			window_from += datetime.timedelta(minutes=5)
			window_to += datetime.timedelta(minutes=5)
			warm = cold = 0
		if topics == "today is warm":
			warm += 1
		elif topics == "today is cold":
			cold += 1