How work if statement in perl whit a hashmap argument?

i have this variable:

my %permit = (
        "activity" => '',
        "type" => '',
        "sub_type" => '',
        "status" => '',e
        );

    my $permit;

and before i have tihis if:

if($permit->{activity}){
     print "inside if\n";
}

the question is: when the if statement is execute?