What's the pythonic way to handle a heterogenous list of ids and database rows

Question

My situation is that I am writing a function that allows a user to delete records from a database. For efficiency, the function itself must be able to take a list of arguments for batch deletion. In addition, for simplicity, the list can contain either IDs (which can be strings or ints) or row objects (which are glorified dicts)

If you are curious, the reason behind allowing full-fledged rows is that there are security checks that examine row data to make sure that the user is allowed to delete the rows in question. Allowing rows to be passed in can reduce trips to the database.

Currently, I use the oft-chastised isinstance function in the following way:

def deleteRows(rowsToDelete):
    ids = set()
    rows = []
    for r in rowsToDelete:
        if isistance(r, basestring) or isinstance(r, int):
            ids.add(r)
        else:
            rows.append(r)
    # Some logic that SELECTS based on the data in ids and appends the
    # result into rows...
    # ... then security ...
    # ... then DELETE

I can see why this is dangerous (what if there is a type can be coerced into an id that isn't an int or basestring?), however I am at a loss for a cleaner solution that doesn't involve isinstance in one way or another, or relying on an exception that may or may not be related to my actual code.

The question is, what is the most effective way of doing this in python? Or, alternatively, is babying the caller this much just a recipe for disaster, i.e. I should just require that the parameter be either a list of types that coerce to an int or a list of rows?

Answer 1

I would recommend not making the interface this flexible. Your code will be simpler to have separate delete_rows(*row_objs) and delete_rows_by_id(*int_ids) the former calling the latter.