#!/usr/bin/perl -w
use strict;
use diagnostics;
use warnings FATAL => 'all';
use Data::Dumper;
$Data::Dumper::Useperl = 1;
$Data::Dumper::Indent = 1;
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Useqq = 1;
$Data::Dumper::Deparse = 1;
use Params::Validate qw(:all);

sub foo {
  validate(
    @_,
    { 'bar' => 1, # mandatory
      'baz' => 0, # optional
    }
  );
  print "Hello Nurse!\n";
}
foo('bar' => "arg1");

sub qux {
  validate(
    @_,
    {}
  );
  print "Empty Hash\n";
}
qux('test');

##</code><code>##

$ perl crap2.pl 
Hello Nurse!
Uncaught exception from user code:
        Odd number of parameters in call to main::qux when named parameters were expected
 at crap2.pl line 25
        main::qux('test') called at crap2.pl line 31
 at crap2.pl line 25
        main::qux('test') called at crap2.pl line 31

##</code><code>##

...
eval { 
  local $SIG{__WARN__} = sub {
    print STDERR "HOOKED __WARN__\n"; 
    print STDERR Carp::longmess();
    return();
  };
  local $SIG{__DIE__} = sub {
    print STDERR "HOOKED __DIE__\n"; 
    print STDERR Carp::longmess();
    exit(1); # or in your case return()
  };
  # Examples - message not printed due to hooks.
  # CORE::warn("Warn Message:\n", @_, "\n");
  # CORE::die("Died Message:\n", @_, "\n");
  $DT = DateTime->new( year => $year, time_zone => $tz ); 
};
return if $@;
...

##</code><code>##

...
eval {
  $tz = DateTime::TimeZone->new( name => 'Europe/London' );
  $DT = DateTime->new( year => $year, time_zone => $tz ); 
};
return if $@;
...