=head3 safe_to_delete

    my $result = $patron->safe_to_delete;

    if ( $result eq 'has_guarantees' ) { ... }

    elsif ( $result ) { ... }

    else { # cannot delete }

This method tells if the Koha:Patron object can be deleted. Possible return values

=over 4

=item 'ok'

=item 'has_checkouts'

=item 'has_debt'

=item 'has_guarantees'

=item 'is_anonymous_patron'

=back

=cut

sub safe_to_delete {

    my ($self) = @_;

    my $anonymous_patron = C4::Context->preference('AnonymousPatron');

    return 'is_anonymous_patron'

        if $anonymous_patron && $self->id eq $anonymous_patron;

    return 'has_checkouts'

        if $self->checkouts->count;

    return 'has_debt'

        if $self->account->outstanding_debits->total_outstanding > 0;

    return 'has_guarantees'

        if $self->guarantee_relationships->count;

    return 'ok';

}