Worked on the CompassionCH/compassion-modules repository to enhance the reliability of birthday-related invoice generation in a backend Python environment. Focused on refining the date calculation logic within the invoicing workflow, the developer updated the compute_date_birthday_invoice function to default the payment date to the current date when none is provided. This adjustment addressed a bug that previously led to misdated invoices, reducing the risk of customer confusion and billing disputes. The work involved updating the wizard-based generation flow, ensuring accurate and consistent invoice dates across billing sources. Demonstrated backend development skills with a focus on robust, traceable bug resolution.