import csv


def read_db(filename="db.csv"):
    """
    Read filename and return a dictionary mapping string names to hash of source
    code of a strategy
    """
    with open(filename, "r") as db:
        csvreader = csv.reader(db)
        str_to_hash = {(row[0], row[1]): row[2] for row in csvreader}
    return str_to_hash