Confused - how to use List/Nested

Can you help me understand how to use the structure like below to achieve something like this:

 {"config":{"factor_1":[{"comparator":"<=", "value":"20"},{"comparator":">=", "value":"10"}],
               "factor_2":[{"comparator":"<=", "value": "PE"}],
               "factor_3":[{"comparator":"exactly", "value": "AAA+"}]}

class ComparatorValue(Schema):
    comparator = fields.Str(required=True)
    value = fields.Str(required=True)

    @validates('comparator')
    def validate_comprator(self, comparator):
        if comparator not in comparators:
            raise ValidationError("Invalid comparator: {}. Allowed values: {}".format(comparator, comparators))

    class Meta:
        strict = True


class ConfigSchema(Schema):
    """
    {"config":{"factor_1":[{"comparator":"<=", "value":"20"},{"comparator":">=", "value":"10"}],
               "factor_2":[{"comparator":"<=", "value": "PE"}],
               "factor_3":[{"comparator":"exactly", "value": "AAA+"}]}
    """
    config = fields.Dict(keys=fields.Str(required=True),
                         values=fields.Nested(ComparatorValue), required=True)
    # comparator = fields.Str()
    # # value = fields.Str(required=True)
    #


    @validates('config')
    def validate_config(self, config):
        keys = list(config.keys())
        vals = list(config.values())
        for key in keys:
            if key != '':
                raise ValidationError("Factor name cannot be empty.")
        # for val in vals:
        #     if

    class Meta:
        strict = True

def get_api():

    class BondScreenApi(Resource):
        @use_args(ConfigSchema())
        def post(self, args):
            # comparator = args['comparator']
            # value = args['value']
            print(args['config'])
            print("Posted args: {}".format(args))
            return {"Got": "Through"}, 201

    return BondScreenApi

As soon as I add Nested/List, it stops working, as in it successfully goes through all of the validation, even though the args are not correct. For example, if for values we have fields.List(Nested(ComparatorValue)) (this is actually what I need, I’ve given above a minimal example), then any request where the data is like: {"config": {"yo":"got through"}} goes through, even though the value of “yo” is supposed to be a List(Nested(...)). I am clearly misunderstanding how to use it and I cannot find a lot of examples on the Internet.

[lafrech]

Depends on your project. Looks like you’re starting something so go for it. Just beware of the updates, pin your versions, read the changelog. We hope to release a 3.0 soonish.

[nazariyv]

Thanks for your help!