Write pretty_money(amount) that returns a non-negative amount as a string with a leading $, commas every three digits, and exactly two decimals.
Examples
Input: amount = 1234.5
Output: "$1,234.50"
Input: amount = 0
Output: "$0.00"
Constraints
0 <= amount <= 10**12
Goals
- Use the comma format option for thousands separators
- Combine it with a fixed number of decimals