sub peek_rfc822_body {
    my ($self, $msg) = @_;
    my $wants_many = undef;
    if (ref($msg) eq 'ARRAY') {
        $msg = join(',', @$msg);
        $wants_many = 1;
    }
    my ($ok, $lines) = $self->_tell_imap(FETCH => "$msg BODY.PEEK[]", 1);
    if ($ok) {
        my @ret = map { $_->[1] } @$lines;
        return $wants_many ? \@ret : $ret[0];
    }
    return undef;
}