Select Code to Download

sub f {
    my ($AoH) = @_;
...
        # do something with $hashref
    }
}

...
# somewhere in your code
...
# and at some other point
f([\%hash]);
...

sub g {
    my ($arrayref_containing_just_one_hashref) = @_;
    my $hashref = $arrayref_containing_just_one_hashref->[0];
    # do something with $hashref
}