Relationship between 3 table class in python, flask and sqlalchemy

Question

I am using Python 3.10 and SQLAlchemy 1.4.29

It has 3 classes User, Post and Comment. A User has many Post instances (1-N relationship). And the hard part is creating the relationship between the post comments and the post, as I need to add the user in the relationship to identify the comment.

Below is the models.py code and the error that is appearing.

error:

sqlalchemy.exc.InvalidRequestError:  One or more mappers failed to
initialize - can't proceed with initialization of other mappers. 
Triggering mapper: 'mapped class Post->post'.

Original exception was:

Error creating backref 'comentarios_do_post' on relationship
'Post.comentarios': property of that name exists on mapper 'mapped
class Comentario->comentario'

code:

from main import database
from datetime import datetime

class Usuario(database.Model):
    id = database.Column(database.Integer, primary_key=True)
    username = database.Column(database.String, nullable=False)
    email = database.Column(database.String, nullable=False, unique=True)
    senha = database.Column(database.String, nullable=False)
    foto_perfil = database.Column(database.String, default='default.jpg')
    posts = database.relationship('Post', backref='autor', lazy=True)
    comentarios = database.relationship('Comentario', backref='autor_do_comentario', lazy=True)


class Post(database.Model):
    id = database.Column(database.Integer, primary_key=True)
    titulo = database.Column(database.String, nullable=False)
    corpo = database.Column(database.Text, nullable=False)
    data_criacao = database.Column(database.DateTime, nullable=False, default=datetime.utcnow())
    like = database.Column(database.Integer, default='0')
    deslike = database.Column(database.Integer, default='0')
    id_usuario = database.Column(database.Integer, database.ForeignKey('usuario.id'), nullable=False)
    comentarios = database.relationship('Comentario', backref='comentarios_do_post', lazy=True)


class Comentario(database.Model):
    id = database.Column(database.Integer, primary_key=True)
    corpo = database.Column(database.Text, nullable=False)
    data_criacao = database.Column(database.DateTime, nullable=False, default=datetime.utcnow())
    id_post = database.Column(database.Integer, database.ForeignKey('post.id'), nullable=False)
    id_usuario = database.Column(database.Integer, database.ForeignKey('usuario.id'), nullable=False)