Here's the `comments.py` file for the `app/api/v1/schemas/` directory in the `blog_app_igblf` FastAPI backend project:

from datetime import datetime
from typing import Optional

from pydantic import BaseModel

class CommentBase(BaseModel):
    content: str

class CommentCreate(CommentBase):
    pass

class CommentUpdate(CommentBase):
    pass

class CommentInDBBase(CommentBase):
    id: int
    post_id: int
    created_at: datetime
    updated_at: Optional[datetime] = None

    class Config:
        orm_mode = True

class Comment(CommentInDBBase):
    pass

class CommentInDB(CommentInDBBase):
    pass

This file defines the following Pydantic models for comments:

4. `CommentInDBBase`: A base model that includes fields for the comment ID (`id`), the associated post ID (`post_id`), the creation timestamp (`created_at`), and an optional update timestamp (`updated_at`). This model inherits from `CommentBase` and includes the `orm_mode` configuration to allow reading data from an SQLAlchemy model.