class Lot: """ Represents an item (or set of items) in an auction: a lot. Attributes: - number (int): A unique identifying number for the lot. - description (str): A description of the lot. - highest_bid (Bid): The current highest bid for this lot. """ def __init__(self, number, description): """ Construct a Lot, setting its number and description. Parameters: - number (int): The lot number. - description (str): A description of this lot. """ self.number = number self.description = description self.highest_bid = None def bid_for(self, bid): """ Attempt to bid for this lot. A successful bid must have a value higher than any existing bid. Parameters: - bid (Bid): A new bid. Returns: - bool: True if the bid is successful, False otherwise. """ if self.highest_bid is None: # There is no previous bid. self.highest_bid = bid return True elif bid.value > self.highest_bid.value: # The bid is better than the previous one. self.highest_bid = bid return True else: # The bid is not better. return False def __str__(self): """ Return a string representation of this lot's details. Returns: - str: A string representation of this lot. """ details = f"{self.number}: {self.description}" if self.highest_bid is not None: details += f" Bid: {self.highest_bid.value}" else: details += " (No bid)" return details def get_number(self): """ Return the lot's number. Returns: - int: The lot's number. """ return self.number def get_description(self): """ Return the lot's description. Returns: - str: The lot's description. """ return self.description def get_highest_bid(self): """ Return the highest bid for this lot. This could be None if there is no current bid. Returns: - Bid or None: The highest bid for this lot, or None if there is no current bid. """ return self.highest_bid class Bid: """ Represents an auction bid. It contains a reference to the Person bidding and the amount bid. Attributes: - bidder (Person): The person making the bid. - value (int): The value of the bid. """ def __init__(self, bidder, value): """ Create a bid. Parameters: - bidder (Person): Who is bidding for the lot. - value (int): The value of the bid. """ self.bidder = bidder self.value = value def get_bidder(self): """ Get the bidder. Returns: - Person: The bidder. """ return self.bidder def get_value(self): """ Get the value of the bid. Returns: - int: The value of the bid. """ return self.value class Person: """ Represents a person who participates in an auction. Attributes: - name (str): The name of the person. """ def __init__(self, name): """ Create a new person with the given name. Parameters: - name (str): The person's name. """ self.name = name def get_name(self): """ Get the person's name. Returns: - str: The person's name. """ return self.name class Auction: """ Represents an auction. Attributes: - lots (list): The list of Lots in this auction. - next_lot_number (int): The number that will be given to the next lot entered into this auction. """ def __init__(self): """ Create a new auction. """ self.lots = [] self.next_lot_number = 1 def enter_lot(self, description): """ Enter a new lot into the auction. Parameters: - description (str): A description of the lot. """ self.lots.append(Lot(self.next_lot_number, description)) self.next_lot_number += 1 def show_lots(self): """ Show the full list of lots in this auction. """ for lot in self.lots: print(lot.__str__()) def make_a_bid(self, lot_number, bidder, value): """ Make a bid for a lot. A message is printed indicating whether the bid is successful or not. Parameters: - lot_number (int): The lot being bid for. - bidder (Person): The person bidding for the lot. - value (int): The value of the bid. """ selected_lot = self.get_lot(lot_number) if selected_lot is not None: bid = Bid(bidder, value) successful = selected_lot.bid_for(bid) if successful: print("The bid for lot number", lot_number, "was successful.") else: highest_bid = selected_lot.get_highest_bid() print("Lot number:", lot_number, "already has a bid of:", highest_bid.get_value()) def get_lot(self, lot_number): """ Return the lot with the given number. Return None if a lot with this number does not exist. Parameters: - lot_number (int): The number of the lot to return. Returns: - Lot or None: The lot with the given number, or None if it does not exist. """ for lot in self.lots: if lot.get_number() == lot_number: return lot print("Lot number:", lot_number, "does not exist.") return None