I have a 3D Keras array named ‘X’. If I print its shape, I get:

```
print(X.shape)
>>> (None, 30, 90)
```

I am asked to slice this 3D Keras array and turn it into this shape: ** (90,)** (so I want to isolate the last dimension)

How do I do this?

I have tried using this (which would work if it was a 3D numpy array): `X[:,t,:]`

, but since I’m using Keras I get:

```
print(X[:,t,:].shape)
>>> (None, 90)
```

Any suggestions?