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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 assets(self, asset_code=None, asset_issuer=None, cursor=None, order='asc', limit=10):
 """This endpoint represents all assets. It will give you all the assets in the system along with various statistics about each. See the documentation below for details on query parameters that are available. `GET /assets{?asset_code,asset_issuer,cursor,limit,order} <https://www.stellar.org/developers/horizon/reference/endpoints/assets-all.html>`_ :param str asset_code: Code of the Asset to filter by. :param str asset_issuer: Issuer of the Asset to filter by. :param int cursor: A paging token, specifying where to start returning records from. :param str order: The order in which to return rows, "asc" or "desc", ordered by asset_code then by asset_issuer. :param int limit: Maximum number of records to return. :return: A list of all valid payment operations :rtype: dict """

        endpoint = '/assets'
        params = self.__query_params(asset_code=asset_code, asset_issuer=asset_issuer, cursor=cursor, order=order,
                                     limit=limit)
        return self.query(endpoint, params)