Adjust date and time to UTC rather than ignoring tzinfo
if isinstance(param_value, list):
request_params[param_name] = ','.join(map(str, param_value))
elif param_name in ("start_time", "end_time") and isinstance(param_value, datetime.datetime):
+ if param_value.tzinfo is not None:
+ param_value = param_value.astimezone(datetime.timezone.utc)
request_params[param_name] = param_value.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
# TODO: Constant datetime format string?
else: