gistfile1.py

class ListedProduct(object):

    def __init__(self, listed_product_tuple):
        """Takes a KeyedTuple and transforms it into a listed product.

        :param listed_product_tuple: A KeyedTuple
        :type listed_product_tuple: sqlalchemy.KeyedTuple

        """
        self.listed_product_tuple

    @property
    def json(self):
        return {
            'id': self.listed_product_tuple.ProductListing.listing_id,
            'category': self.listed_product_tuple.Categories.name,
            # etc...
        }


class ProductListing(...):
    # ...

    @classmethod
    def get(cls):
        return [ListedProduct(each) for each in cls.big_ole_join()]