Boto3 Dynamo DB query set FilterExpression to None?

Question

Hi I have a couple queries I want to run on Dynamo DB, since the query FilterExpression depends on some condition I want to set it as a variable like this:

    if valid_attr:
        filter_expression = Attr('keyName').is_in(valid_attr)
    else:
        filter_expression = None

But it seems that boto3 doesn't like None values, is there some other way to do something similar? I don't want duplicated code in my script. I can't find what are the default parameters from documentation.

Answer 1

I did as following

query_parameters = {attr1: value1, attr2: value2}
if valid_attr:
    query_parameters.update({'FilterExpression': Attr('keyName').is_in(valid_attr)})
table.query(**query_parameters)