Add 'use warnings' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.

Error: Sah::Schema::perl::comparer::modname, Sah::Schema::perl::comparer::modname_with_optional_args, Sah::Schema::perl::comparer::modnames, Sah::Schema::perl::comparer::modnames_with_optional_args, Sah::Schemas::Comparer