Generated bubble graph do not validate with bubbletools

I generated a bubble graph with:
```
import powergrasp
with open("graph.bbl", "w") as fd:
for line in powergrasp.compress_by_cc("graph.gml"):
fd.write(line + '\n')
```
Then, I wanted to check if it generated a correct bubble file with [bubbletools](https://github.com/Aluriak/bubble-tools):
```
from bubbletools import validate
for log in validate(open("graph.bbl", "r"), profiling=True):
print(log)
```
I got the following error:

ValueError: Input line "# CONNECTED COMPONENT 1
" is not bubble formatted