use strict;
use warnings;
use feature 'say';
use Time::Piece;
use Class::Unload;

eval { say gmtime->datetime; 1 } or say $@;

Class::Unload->unload('Time::Piece');

eval { say gmtime->datetime; 1 } or say $@;

require Time::Piece;

eval { say gmtime->datetime; 1 } or say $@;

__END__

##</code><code>##

$ perl monks/11105002.pl

2019-08-25T22:43:52
Can't locate object method "gmtime" via package "Time::Piece" at /Users/1nickt/perl5/perlbrew/perls/perl-5.30.0/lib/5.30.0/darwin-2level/Time/Piece.pm line 143.

2019-08-25T22:43:52