Implement FinanceAgent - Python financial analysis library

[Copilot]

Implements a standalone Python library for financial calculations and transaction tracking with no external dependencies.

Core Functionality

Financial Calculators:

• Compound interest with configurable compounding periods
• Simple interest
• ROI (Return on Investment)
• Monthly loan payments via amortization

Transaction Management:

• Income/expense tracking with type validation
• Balance and summary calculations
• JSON import/export with structure validation

API Example

from finance_agent import FinanceAgent

agent = FinanceAgent()

# Calculate compound interest
amount = agent.calculate_compound_interest(
    principal=10000, 
    rate=0.05, 
    time=10, 
    compounds_per_year=12
)  # Returns: 16470.09

# Track transactions
agent.add_transaction(5000, "income", "Salary")
agent.add_transaction(1200, "expense", "Rent")
summary = agent.get_summary()  # {'balance': 3800.00, ...}

# Persist data
agent.export_transactions("data.json")

Implementation Details

• Full type hints and input validation across all methods
• Comprehensive error handling for file I/O (FileNotFoundError, JSONDecodeError, IOError)
• Transaction type enforcement (only 'income'/'expense' accepted)
• 21 unit tests covering all functionality and edge cases
• Package configuration via setup.py for pip installation

Files Added

• finance_agent.py - Core FinanceAgent class
• test_finance_agent.py - Test suite
• example.py - Usage demonstrations
• setup.py - Package metadata
• LICENSE - MIT
• Updated README.md with API reference

Original prompt

FinanceAgent

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