first chapter

models/address.py

@@ -0,0 +1,9 @@
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+
+class Address(BaseModel):
+    street: str
+    house_number:  int | str
+    city: str

models/character.py

@@ -0,0 +1,18 @@
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+from models.address import Address
+from models.user import User, UserFieldValidator
+
+
+class CharacterModel(BaseModel):
+    role: str
+    user: User
+    address: Address
+
+class CharacterModelOptionalAddress(BaseModel):
+    role: str
+    user: UserFieldValidator
+    address: Address | None = None
+

models/user.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from typing import Union, Optional
-from pydantic import BaseModel, PositiveInt, field_validator, Field
+from pydantic import BaseModel, PositiveInt, field_validator, Field, ValidationError
 
 
 class User(BaseModel):
@@ -38,24 +38,28 @@ class UserPositiveInt(BaseModel):
 class UserFieldValidator(BaseModel):
     name: str
     surname: str
-    age: PositiveInt | None
+    age: int | None
     registered: bool = False
 
     @field_validator("age")
     def validate_age(cls, value):
+        if value < 0:
+            raise ValidationError("age must be positive")
         if value < 18:
-            raise ValueError("age must be at least 18")
+            raise ValidationError("age must be at least 18")
         return value
 
 
 class UserMaxLength(BaseModel):
     name: str = Field(..., max_length=10)
-    surname: str = Field(..., max_length=10)
-    age: PositiveInt | None
+    surname: str = Field(..., max_length=12)
+    age: int | None
     registered: bool = False
 
     @field_validator("age")
     def check_age(cls, value):
+        if value < 0:
+            raise ValidationError("age must be positive")
         if value < 18:
             raise ValueError("You are too young to register")
         return value