What's my Cache::Memcached::Fast $class = shift; for in Perl?

Question

my Cache::Memcached::Fast $class = shift;

I've been using my $class = shift;,

what's Cache::Memcached::Fast here for?

When do we have to prefix variables with package name when declaring?

Answer 1

When do we have to prefix variables with package name when declaring?

Never, in modern Perl. Types in my are only used with the deprecated fields pragma (e.g, restricted hashes). Don't use them in new code.