def interface(self, iface_name):
        """
        Returns the interface with the given name, or raises RpcException if no interface matches
        """
        if self.has_interface(iface_name):
            return self.interfaces[iface_name]
        else:
            raise RpcException(ERR_INVALID_PARAMS, iface_name % "Unknown interface: '%s'")
dataset/ETHPy150Open StackHut/stackhut/stackhut_toolkit/common/barrister/runtime.py/Contract.interface/swapped operands of `%`