use strict;
use warnings; 
use Data::Dumper;

my %a = (-keys   => 'v1',
         -values => 'v2');
         
print Dumper(\%a);

##</code><code>##

$VAR1 = {
          '-keys' => 'v1',
          '-values' => 'v2'
        };

##</code><code>##

my %a = (-keys   , 'v1',
         -values , 'v2');

##</code><code>##

Not enough arguments for keys at C:\gash.pl line 6, near "keys   ,"
Not enough arguments for values at C:\gash.pl line 7, near "values ,"

##</code><code>##

my %a = (-xkeys   , 'v1',
         -xvalues , 'v2');

##</code><code>##

$VAR1 = {
          '-xvalues' => 'v2',
          '-xkeys' => 'v1'
        };