throws required key not provided when submit comments using REST API 2.0

I solved my issue. I had to add headers to my curl

-H "Content-Type: application/json"

and in python it's now

resp = requests.post(url, data=json.dumps(payload), auth=(self.vcs_user, self.vcs_token), headers={'Content-Type': 'application/json'})

 All better.

Same issue in python, and similar from the curl command line. Smells like a bug.

python3:

url = f'https://api.bitbucket.org/2.0/repositories/{company}/{repo}/pullrequests/{pr_id}/comments'
payload = {
    "content": {
        "raw": "robo comment",
    }
}
resp = requests.post(url, data=payload, auth=(self.vcs_user, self.vcs_token))
print(resp.content)

b'{"type": "error", "error": {"fields": {"content": "expected a dictionary"}, "message": "Bad request"}}'

curl:

$ curl -X POST -H "Authorization: Bearer MDkwg89afxxxxxxxxxxxxxxxxxx" -d '{ "content": { "raw": "some comment" }}' https://api.bitbucket.org/2.0/repositories/<company>/<repo>/pullrequests/<pull_id>/comments
{"type": "error", "error": {"fields": {"content": "required key not provided", "{ \"content\": { \"raw\": \"some comment\" }}": "extra keys not allowed"}, "message": "Bad request"}}

Could you solve it?