Correct Way to Write in Python

[Peter Otten]

punk.sagar at gmail.com wrote:

> Hi All,
> 
> Im new to Python. Im coming from C# background and want to learn Python.
> I was used to do following thing in C# in my previous experiences. I want
> to know how do I implement below example in Python. How these things are
> done in Python.
> [code]
> public class Bank
> {
> 
> public List<Customer> lstCustomers = new List<Customer>();
> private string micrcode;
> 
> public void Bank()
> {
> customer
> }
> 
> }
> 
> public class Customer
> {
> private srting customername;
> 
> public string CustomerName
> 
> {
> get { return customername; }
> set { customername = value; }
> }
> }
> 
> main()
> {
> Customer objCustomer = new Customer;
> objCustomer.CustomerName = "XYZ"
> 
> Bank objBank = new Bank();
> objBank.lstCustomer.Add(objCustomer);
> 
> }
> [/code]

While I don't know C# I doubt that this is good C# code ;)
Here's a moderately cleaned-up Python version:

class DuplicateCustomerError(Exception):
    pass

class Customer:
    def __init__(self, name):
        self.name = name

class Bank:
    def __init__(self):
        self.customers = {}
    def add_customer(self, name):
        if name in self.customers:
            raise DuplicateCustomerError
        customer = Customer(name)
        self.customers[name] = customer
        return customer

if __name__ == "__main__":
    bank = Bank()
    bank.add_customer("XYZ")

I'm assuming a tiny bank where every customer has a unique name and only one 
program is running so that you can ignore concurrency issues.