I have this in my file

```py
import re

sample = """Name: @s
Owner: @a[tag=Admin]"""

target = r"@[sae](\[[\w{}=, ]*\])?"
regex = re.split(target, sample)

print(regex)

```

I want to split all words that start with `@`, so like this:  

`["Name: ", "@s", "\nOwner: ", "@a[tag=Admin]"]`

But instead it give this:  

`['Name: ', None, '\nOwner: ', '[tag=Admin]', '']`

How to seperating it?