详细举例This code represents a class named "PropertyManagementCompany" which manages a portfolio of real estate properties. The class has a name, liquidity and a set of properties that it manages. The liquidity represents the amount of money the company has available to purchase new properties or sell existing ones. The class has two constructors, one that creates an empty portfolio and sets the liquidity to zero, and another that takes a list of properties and adds them to the portfolio. Both constructors also require the company name and liquidity as parameters. The class has two methods to buy and sell real estate properties. The "buyProperty" method takes a property and a purchase price as parameters and adds the property to the portfolio if the company has enough liquidity to buy it. The "sellProperty" method takes a property and removes it from the portfolio while adding the property's current valuation to the company's liquidity. The class also has getters for the name, liquidity, and portfolio. The "checkName" method is a private helper method that checks if the company name is empty and throws an exception if it is. Overall, this code uses encapsulation to hide the implementation details of the PropertyManagementCompany class. The class has private fields that can only be accessed through its public methods. This approach makes the code more modular and easier to maintain.

class PropertyManagementCompany:
    def __init__(self, name, liquidity, properties=None):
        self.checkName(name)
        self.name = name
        self.liquidity = liquidity
        if properties is None:
            self.portfolio = []
        else:
            self.portfolio = properties

    def buyProperty(self, property, purchasePrice):
        if self.liquidity >= purchasePrice:
            self.portfolio.append(property)
            self.liquidity -= purchasePrice

    def sellProperty(self, property):
        if property in self.portfolio:
            self.portfolio.remove(property)
            self.liquidity += property.currentValuation

    def getName(self):
        return self.name

    def getLiquidity(self):
        return self.liquidity

    def getPortfolio(self):
        return self.portfolio

    def checkName(self, name):
        if name == '':
            raise ValueError('Company name cannot be empty.')

For example, we can create a new PropertyManagementCompany as follows:

properties = [Property('123 Main St.', 100000), Property('456 Oak Ave.', 200000)]
company = PropertyManagementCompany('ABC Company', 500000, properties)

This creates a company named "ABC Company" with $500,000 liquidity and a portfolio containing two properties. We can then buy a new property and sell an existing property using the `buyProperty` and `sellProperty` methods:

newProperty = Property('789 Elm St.', 150000)
company.buyProperty(newProperty, 150000)

propertyToSell = properties[0]
company.sellProperty(propertyToSell)

This would add the new property to the portfolio and remove the first property from the portfolio while adding its current valuation to the company's liquidity.