Description

Adds clarifying note explaining why importing Pydantic's BaseModel is necessary
for request body validation in FastAPI.

Problem

The current tutorial shows the import without explaining its purpose, which can
confuse beginners who may not be familiar with Pydantic or understand why this
specific import is required.

Solution

Added a note block explaining that:

• BaseModel is the foundation for data validation
• It's required for creating validated request body models
• FastAPI uses it for automatic validation and documentation

Impact

Helps beginners understand the relationship between Pydantic and FastAPI, reducing
confusion at the start of the tutorial.

Type of Change

• Documentation improvement
• Bug fix
• New feature
• Breaking change

Checklist

• Documentation follows style guide
• Change improves clarity for beginners
• No technical errors introduced
• Consistent with other tutorial notes

Related Issues

Addresses common beginner confusion mentioned in community discussions about
understanding Pydantic's role in FastAPI.