def normalize_proportions(proportions):
    """
    Proportions specified in config file are all just relative - this normalizes them to a proportion out of 1.0
    :param proportions: The proportions dictionary generated by parse_config_file
    :return: A dictionary in the same format as that generated by parse_config_file, but with normalized values.
    """
    # First, get total number specified.
    total_count = 0.0
    for strain in proportions:
        total_count += proportions[strain]
    # Now modify all counts by dividing by total number so that sum of proportions adds to 1.
    for strain in proportions:
        proportions[strain] = proportions[strain]/total_count
    return proportions