If you have an array of hashes then your getter would need an index (a number) and a key value to get at the the data.

Perhaps something like this:

#!/usr/bin/perl

use strict;
use warnings;

{
  package Item;
  
  sub new {
    my ($class) = @_;
    my $self = [
      {fld1 => 1, fld2 => 2},
      {fld1 => 3, fld2 => 4},
    ];
    bless $self, $class;
  }
  
  sub get_fld {
    my ($self, $rec, $fld) = @_;
    return $self->[$rec]{$fld};
  }
  
}

my $item = Item->new;
my $fld = $item->get_fld(1, 'fld1');
print "$fld\n";
[download]

outputs 3