Salesforce Anon Apex to delete from connected object through lookup on child

delete where exists in list.cls

//Make a list of ID's of addresses on Suppliers : List 1
List< Supplier__c > supList = [ SELECT Id,Address__c FROM Supplier__c ];
List<Id> supids = new List<Id>(new Map<Address__c,Supplier__c>(supList).keySet());

//Make a list of all address IDs : List 2
List< Address__c > AdrList = [ SELECT Id FROM Address__c ];
List<Id> adrids = new List<Id>(new Map<Id,Address__c>(AdrList).keySet());

//Make a list of ID's in List 2 which are not in List 1 : List 3
list< Id > List3 =[ SELECT Id FROM Address__c where Id not in:adrids Limit 1];

// Delete list 3
Database.DeleteResult[] deleteResults = Database.delete(List3, true);
for(Database.DeleteResult dr : deleteResults) {                   
    if (!dr.isSuccess()) {
        for(Database.Error err : dr.getErrors()) {
            System.debug(LoggingLevel.Error, 'The following error has occurred.'
                + '\n' + err.getStatusCode() + ': ' + err.getMessage()
                + '\n fields that affected this error: ' + err.getFields());
            // Plus further error handling as required
        }
    }
}