##
Package::Stash->new( $yaml_class )->has_symbol( '&Dump' )
or croak( "Can't find Dump in $yaml_class\n" );
##
##
my $Dump = $yaml_class . "::Dump";
[... later in the code ...]
my $var = eval { &$Dump(...) } or croak( "bad return or Dump not implemented\n" );