feat(other): add basic BankAccount OOP class (v3)

[nickzerjeski]

Describe your change:

Fixes #14024

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[Copilot]

Pull request overview

Adds a new BankAccount class under other/ intended to demonstrate basic OOP concepts (encapsulation via properties, simple state updates) and includes inline doctests.

Changes:

• Introduces BankAccount with validated initialization, balance accessor, deposit(), and withdraw().
• Adds doctest examples in the class docstring and a __main__ doctest runner.

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[Copilot]

The module docstring doesn’t include any source/explanation URL. New submissions in this repo typically include at least one link in the header docstring/comment to help readers (see CONTRIBUTING.md:57 and e.g. other/graham_scan.py:2-6). Consider adding a relevant reference link for the concept being demonstrated.

Suggested change

	Simple BankAccount class demonstrating core OOP concepts.
	Simple BankAccount class demonstrating core OOP concepts.
	Reference:
	https://docs.python.org/3/tutorial/classes.html

[Copilot]

The doctests currently cover only the happy path. This repo often includes doctests for erroneous inputs/exceptions as well (e.g., financial/interest.py:20-31). Consider adding doctests for the validation branches (empty account_number, negative initial_balance, non-positive deposit/withdraw, withdraw exceeding balance) to ensure those errors are exercised.

Suggested change

	'ACC-1001'
	'ACC-1001'
	>>> BankAccount("", initial_balance=10.0)
	Traceback (most recent call last):
	...
	ValueError: account_number must be provided
	>>> BankAccount("ACC-1002", initial_balance=-1.0)
	Traceback (most recent call last):
	...
	ValueError: initial_balance cannot be negative
	>>> account.deposit(0)
	Traceback (most recent call last):
	...
	ValueError: deposit amount must be positive
	>>> account.withdraw(0)
	Traceback (most recent call last):
	...
	ValueError: withdraw amount must be positive
	>>> account.withdraw(1000)
	Traceback (most recent call last):
	...
	ValueError: insufficient funds

[Copilot]

This file reads more like an OOP tutorial/example than an algorithm or data-structure implementation, which may conflict with the project’s contribution guidelines about avoiding “how-to examples” and focusing on algorithms with unique computational value (CONTRIBUTING.md:41-62). If it’s intended to stay, consider clarifying in the module/class docstring what algorithmic concept is being implemented and why it belongs in this repository.

Suggested change

	Simple BankAccount class demonstrating core OOP concepts.
	"""
	class BankAccount:
	"""
	Basic bank account model with encapsulated account number and balance.
	Invariant-preserving bank account state model.
	This module implements a minimal transactional data model whose computational
	value is the enforcement of account invariants during constant-time state
	transitions: account identifiers must be present, balances may not start
	negative, deposits must be positive, and withdrawals may not overdraw the
	account.
	"""
	class BankAccount:
	"""
	Stateful account abstraction with validated balance updates.
	The class is intentionally small, but its purpose is not to serve as a
	generic OOP tutorial. It provides a compact example of how to model a
	mutable record while preserving correctness constraints across operations,
	with each transaction executing in O(1) time.