I got `AssertionError: wrong values for ft`

. Iβm wondering do we need to use sigma as equation 1?

```
πͺβ¨π‘β©π=π(ππ[πβ¨π‘β1β©,π±β¨π‘β©]+ππ)
```

I implemented the formula without sigma, because it is not explained in the descriptions.

```
ft = np.dot(Wf, concat) + bf
```