my (
    $self, 
    #@type Foo::Bar
    $foobar,
    #@type Foo::Baz
    $foobaz
) = @_;

##</code><code>##

#@returns Some::Class
#@arg $arg1 Foo::Bar    # some description
#@arg $arg2 Foo::Baz    
#@arg $arg3             # just a description
#@arg %args key1, key2 Foo::Zoo, key3 
sub somesub{
    my ($self, $arg1, $arg2, $arg3, %args) = @_;
}

##</code><code>##

#@arg [$var1 HashRef[Foo::Bar]] # description
or
#@arg optional $var1 HashRef[Foo::Bar] # description
or 
#@oarg $var1 HashRef[Foo::Bar] # description