import time


def datetime_to_ms(dt):
    """
    Convert an unaware datetime object to milliseconds. This will
    be a UTC time. The SMC stores all times in UTC and will do the
    time conversions based on the local timezone.
    Example of converting a datetime to milliseconds::
    
        utc_time = datetime.strptime("2018-06-04T00:00:00", "%Y-%m-%dT%H:%M:%S")
        datetime_to_ms(utc_time)
    
    :param dt datetime: pass in python datetime object.
    :return: value representing the datetime in milliseconds
    :rtype: int
    """
    return int(time.mktime(dt.timetuple()) * 1000)