# 1. Goal
Refactor the legacy function module {{P}}BOWL_FEE_OLD in place. The behavior must
stay the same. Improve the code quality so that the module is easier to maintain.

# 2. Open questions
None.

# 3. Context
- Function group {{P}}FG_BOWL exists in package $TMP.
- Function module {{P}}BOWL_FEE_OLD exists in this group. It is the legacy
  implementation of the bowling fee calculation.
- The booking program calls this function module. The interface must not change.

# 4. Contract
- Refactor the function module {{P}}BOWL_FEE_OLD in function group {{P}}FG_BOWL.
- Keep the exact interface: the same parameter names, types, and exceptions.
- The function module name stays the same.

# 5. Business rules
The business rules are defined by the current behavior of the legacy code.
Read the legacy source code in {{P}}BOWL_FEE_OLD. The refactored function module
must produce exactly the same results as the legacy code for every input.
Do not change any rule.

# 6. Constraints
- Release target: SAP_BASIS 816.
- Coding standards: Clean ABAP. Use modern ABAP syntax. No obsolete statements
  (for example COMPUTE, MOVE, ADD ... TO ...). Methods below 40 statements.
  Pass large parameters by reference. No ATC priority 1 or 2 findings.
- Out of scope: do not change the function group {{P}}FG_BOWL. Do not change
  the function module interface.

# 7. Acceptance
- The function module is active and has no syntax error.
- The hidden tests pass.
- Write ABAP Unit tests for the function module in a global test class.