def update_cer(self, symbol, cer, account=None):
        """ Update the Core Exchange Rate (CER) of an asset

            :param str symbol: Symbol of the asset to publish feed for
            :param bitshares.price.Price cer: Core exchange Rate
            :param str account: (optional) the account to allow access
                to (defaults to ``default_account``)

        """
        assert isinstance(
            cer, Price
        ), "cer needs to be instance of `bitshares.price.Price`!"
        if not account:
            if "default_account" in self.config:
                account = self.config["default_account"]
        if not account:
            raise ValueError("You need to provide an account")
        account = Account(account, blockchain_instance=self)
        asset = Asset(symbol, blockchain_instance=self, full=True)
        assert (
            asset["id"] == cer["base"]["asset"]["id"]
            or asset["id"] == cer["quote"]["asset"]["id"]
        ), "Price needs to contain the asset of the symbol you'd like to produce a feed for!"

        cer = cer.as_base(symbol)
        if cer["quote"]["asset"]["id"] != "1.3.0":
            raise ValueError("CER must be defined against core asset '1.3.0'")

        options = asset["options"]
        options.update({"core_exchange_rate": cer.as_base(symbol).json()})
        op = operations.Asset_update(
            **{
                "fee": {"amount": 0, "asset_id": "1.3.0"},
                "issuer": account["id"],
                "asset_to_update": asset["id"],
                "new_options": options,
                "extensions": [],
                "prefix": self.prefix,
            }
        )
        return self.finalizeOp(op, account["name"], "active")
Update the Core Exchange Rate (CER) of an asset

            :param str symbol: Symbol of the asset to publish feed for
            :param bitshares.price.Price cer: Core exchange Rate
            :param str account: (optional) the account to allow access
                to (defaults to ``default_account``)