def load_book_supply(cli_supply, book_supply):
    """
    Updates CLI supply with supply from campaign book.
    But do not overwrite CLI supply with book supply - values from CLI have bigger priority.
    """
    for var, val in book_supply.items():
        if var not in cli_supply:
            cli_supply[var] = val.format(**cli_supply) if isinstance(val, str
                ) else val
