When dealing with values that may be absent or null, always use explicit optional type wrappers instead of implicit null checks or nullable types without clear type constraints. This makes the code's intent clearer, prevents null reference errors, and improves type safety. In Perl, use `Maybe[Type]` to clearly indicate a value could be absent: ```perl has 'sum_metric' => (is => 'rw', isa => 'Maybe[Num|ArrayRef[Num]|PDL]'); ``` In C++, use appropriate optional containers like `dmlc::optional` (or `std::optional` in C++17) when a parameter might not have a value: ```cpp dmlc::optional shifted_output; // Clearly indicates this boolean might not be set ``` Be explicit about which values can be null and provide appropriate methods to safely access or transform these values. When working with optional types, ensure consistent handling across the codebase rather than using ad-hoc null checks. This pattern helps catch null-related errors at compile time rather than runtime.