import csv


def read_raw_data(filename):
    """
    Reads raw data from filename and returns it as 
    list of lists.

    filename:
        File to read from.

    returns:
        list of lists of data, where each sub list is
        is a row, and each sub list item is a row value
    """
    with open(filename, 'r') as raw_data_file:
        raw_data_reader = csv.reader(raw_data_file)
        raw_data = list(raw_data_reader)
        return raw_data