How do you define multiqubit noise channels and noisy training?

Hi there, 

Sorry for the noob question. 

Is is possible to define multi qubit noise channels and use tfq to do noisy training? 

My work flow is similar to that of the tutorials with noise, but instead I'm trying to define the channel

`cirq.asymmetric_depolarize(error_probabilities={'XX': 0.1})`

This throws errors which vanish upon removing this channel. 

Thanks!

Max

