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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def field2choices(self, field, **kwargs):
 """Return the dictionary of OpenAPI field attributes for valid choices definition :param Field field: A marshmallow field. :rtype: dict """

        attributes = {}

        comparable = [
            validator.comparable
            for validator in field.validators
            if hasattr(validator, "comparable")
        ]
        if comparable:
            attributes["enum"] = comparable
        else:
            choices = [
                OrderedSet(validator.choices)
                for validator in field.validators
                if hasattr(validator, "choices")
            ]
            if choices:
                attributes["enum"] = list(functools.reduce(operator.and_, choices))

        return attributes