my %groups = (
	'GroupID1' => true,
	'GroupID2' => false
);
$email_address = lc('member_email');
$subscriber_hash = md5_hex( $email_address );
my $response = $mailchimp->update_member (
	list_id  => 'listid',
	subscriber_hash => $subscriber_hash,
    interests => \%groups
);