i have a list of list with:

```
[['9.2','8.7'],['7.5','6.5']]

```

and i want to convert them into float values to get:

```
[[9.2,8.7],[7.5,6.5]]

```

I've tried this but it doesn't work.

```
L = [['9.2','8.7'],['7.5','6.5']]
for line in L:
    if line:
        line = [float(i) for i in line]
print(L)

```