can someone please tell me why I cant remove the empty string by using following code?

```
numlist = list()

tim = "s x s f f f"
timo = tim.strip()
for line in timo:

    numlist.append(line)

list(filter(None, numlist))

print(numlist)

```

output: `['s', ' ', 'x', ' ', 's', ' ', 'f', ' ', 'f', ' ', 'f']`

desired output: `['s', 'x', 's', 'f', 'f', 'f']`