import datetime
import pytz


def popcorn(filetype="png"):
    """
        Get a datetime string and return it formatted for use as a filename.
    """

    time_of_shot = datetime.datetime.now(pytz.utc)
    formated_time = time_of_shot.strftime("quickshot_%Y-%m-%dT%H_%M_%S_%f")

    return "{}.{}".format(formated_time, filetype)