from datetime import datetime


def format_time_from_arg(time_string):
    """
    Format a time string from args and return a datetime.

    :param time_string: String of the form HH:MM:SS.
    :type time_string: str
    :return: datetime
    """
    time_from_arg = datetime.strptime(time_string, '%H:%M:%S')
    current_time = datetime.today()
    check_time = time_from_arg.replace(year=current_time.year, month=current_time.month, day=current_time.day)
    return check_time