[Python] JWT token error: input should be a valid string

I’m trying to follow Sanjeev’s tutorial on python API developement (https://www.youtube.com/watch?v=0sOvCWFmrtA 1). Until 7,5 hours I didn’t get any trouble, but now I’m trying to create a new post in postman, using a JWT token as authentication. When I try to do this, I get this error:

“pydantic_core._pydantic_core.ValidationError: 1 validation error for TokenData id Input should be a valid string [type=string_type, input_value=14, input_type=int]”

I'm pretty sure I've followed along with the tutorial and that the token is a string, so I don't know where it's going wrong. I’ll try to provide all the relevant code, but if you’re missing something, please let me know.

From schemas.py:

class TokenData(BaseModel):
id: Optional[str]


From oauth2.py:

from jose import JWTError, jwt
from datetime import datetime, timedelta
from . import schemas
from fastapi import Depends, status, HTTPException
from fastapi.security import OAuth2PasswordBearer

oauth2_scheme = OAuth2PasswordBearer(tokenUrl='login')


SECRET_KEY = "b8b33abbff04e43b4a43aed2ab1cc44e962d236caee378dcccce9dc46a3a5592"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30


def create_access_token(data: dict):
to_encode = data.copy()
expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
to_encode.update({"exp": expire})
encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

return encoded_jwt


def verify_access_token(token: str, credentials_exception):
try:
payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
id: str = payload.get("user_id")
if id is None:
raise credentials_exception
token_data = schemas.TokenData(id=id)

except JWTError:
raise credentials_exception

return token_data


def get_current_user(token: str = Depends(oauth2_scheme)):
credentials_exception = HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail=f'Could not validate credentials', headers={'WWW-Authenticate': 'bearer'})
return verify_access_token(token, credentials_exception)


From post.py:

@router.post("/", status_code=status.HTTP_201_CREATED, response_model=schemas.Post)
def create_post(post: schemas.PostCreate, db: Session = Depends(get_db), user_id: int = Depends(oauth2.get_current_user)):
print(user_id)
new_post = models.Post(**post.model_dump())
db.add(new_post)
db.commit()
db.refresh(new_post)
return new_post


I've tried to add ': str' behind several values, but it doesn't change the outcome.

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