example of perl subroutine taking arguments

gistfile1.txt

sub get_latlong_matching_airports {
    my ($parm1, $parm2, $parm3, $parm4) = @_;
    my %args = (
        airports => $parm1,
        lat      => $parm2,
        long     => $parm3,
        max      => $parm4,
        # @_ # this I was not sure of how it worked in the subroutine with defined keys but undefined values
    );
    
    But if I understand what you are saying then
    
    sub get_latlong_matching_airports {
    my %args = (
        airports => undef,
        lat      => undef,
        long     => undef,
        max      => undef,
        @_
    );  # then something like get_latlong_matching_airports('Gatwick', 52.40, 1.07, 30) would be slurped by @_ at the bottom
    of the subroutine get_latlong_matching_airports and become the values to the keys
    so that 
    airports => 'Gatwick',
    lat => 52.40,
    long => 1.07,
    max => 30,
    would be the result of the values passed by @_ at the bottom of the hash %args?