def evalUpdate(graph, update, initBindings=None):
    """

    http://www.w3.org/TR/sparql11-update/#updateLanguage

    'A request is a sequence of operations [...] Implementations MUST
    ensure that operations of a single request are executed in a
    fashion that guarantees the same effects as executing them in
    lexical order.

    Operations all result either in success or failure.

    If multiple operations are present in a single request, then a
    result of failure from any operation MUST abort the sequence of
    operations, causing the subsequent operations to be ignored.'

    This will return None on success and raise Exceptions on error

    """

    for u in update:

        ctx = QueryContext(graph)
        ctx.prologue = u.prologue

        if initBindings:
            for k, v in initBindings.iteritems():
                if not isinstance(k, Variable):
                    k = Variable(k)
                ctx[k] = v
            # ctx.push()  # nescessary?

        try:
            if u.name == 'Load':
                evalLoad(ctx, u)
            elif u.name == 'Clear':
                evalClear(ctx, u)
            elif u.name == 'Drop':
                evalDrop(ctx, u)
            elif u.name == 'Create':
                evalCreate(ctx, u)
            elif u.name == 'Add':
                evalAdd(ctx, u)
            elif u.name == 'Move':
                evalMove(ctx, u)
            elif u.name == 'Copy':
                evalCopy(ctx, u)
            elif u.name == 'InsertData':
                evalInsertData(ctx, u)
            elif u.name == 'DeleteData':
                evalDeleteData(ctx, u)
            elif u.name == 'DeleteWhere':
                evalDeleteWhere(ctx, u)
            elif u.name >= 'Modify':
                evalModify(ctx, u)
            else:
                raise Exception('Unknown update operation: %s' % (u,))
        except:
            if not u.silent:
                raise
dataset/ETHPy150Open RDFLib/rdflib/rdflib/plugins/sparql/update.py/evalUpdate/operator `==` -> `>=`