Get a valid time stamp without illegal characters.
    Adds time_ to make the time stamp a valid table name in sql.
    :return: String, extracted timestamp

def get_valid_time_stamp():
    """
    Get a valid time stamp without illegal characters.
    Adds time_ to make the time stamp a valid table name in sql.
    :return: String, extracted timestamp
    """
    time_stamp = str(datetime.datetime.now())
    time_stamp = "time_" + time_stamp.replace("-", "_").replace(":", "_").replace(" ", "_").replace(".", "_")
    return time_stamp