Update docs/basics/extract.mdx

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

Author: victlue

docs/basics/extract.mdx

@@ -206,7 +206,7 @@ const apartments = await page.extract({
 ```
 
 ```python Python
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
 
 class Apartment(BaseModel):
     address: str = Field(..., description="the address of the apartment")