#CALLING sequence
get_info ('first_name' => 'John',
           'last_name' => 'Doe'); 
#Implementation:
sub get_info {
    my %param = @_;
    die "ERROR: First-name is required" unless $param{first_name};
    die "ERROR: Last-name is required" unless $param{last_name};

   print "Your name is $param{first_name} $param{last_name}\n";
}