from typing import Dict

def express_checkout(product_to_quantity: Dict[str, int]) -> bool:
    """Return True iff the grocery order in product_to_quantity qualifies for the
    express checkout. product_to_quantity maps products to the numbers of those
    items in the grocery order.
    
    >>> express_checkout({'banana': 3, 'soy milk': 1, 'peanut butter': 1})
    ???
    >>> express_checkout({'banana': 3, 'soy milk': 1, 'twinkie': 5})
    ???
    """