human
I wrote the below code

    logging.warning('WARNING:    this    tool    can    modify    low-level    DynamoDB    tables    and    attributes    and    should    be    used    with    caution.    For    example,    modifying    a    photo    or    adding    a    label    directly    will    not    update    secondary    indexes    nor    create    user    updates.')
    def _OnInit(verified_schema):
        if (options.options.op == 'list'):
            def _OnList(result):
                logging.info(result)
                callback()
            db_client.DBClient.Instance().ListTables(callback=_OnList)
        else:
            if (options.options.tables == 'ALL'):
                tables = vf_schema.SCHEMA.GetTables()
            else:
                tables = [vf_schema.SCHEMA.GetTable(n) for n in options.options.tables]
            assert tables, 'no    tables    were    specified'
            with util.Barrier(callback) as b:
                for table in tables:
                    RunOpOnTable(db_client.DBClient.Instance(), table, options.options.op, b.Callback())
    db_client.InitDB(vf_schema.SCHEMA, callback=_OnInit, verify_or_create=options.options.verify_or_create)

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def RunDBA(callback):