"price": None,
            "owner_ids": None,
        },
        {
            "name": "bar",
            "date": datetime(2021, 7, 26).isoformat(),
            "price": 1.0,
            "owner_ids": None,
        },
        {
            "name": "baz",
            "date": datetime(2021, 7, 26).isoformat(),
            "price": 2.0,
            "owner_ids": [1, 2, 3],
        },
    ]

        "price": 1.0,
        "owner_ids": None,
    }


def test_validlist():
    response = client.get("/items/validlist")
    response.raise_for_status()
    assert response.json() == [
        {"aliased_name": "foo", "price": None, "owner_ids": None},
        {"aliased_name": "bar", "price": 1.0, "owner_ids": None},
        {"aliased_name": "baz", "price": 2.0, "owner_ids": [1, 2, 3]},
    ]

    assert response.json() == {"name": "coerce", "price": 1.0, "owner_ids": None}


def test_validlist():
    response = client.get("/items/validlist")
    response.raise_for_status()
    assert response.json() == [
        {"name": "foo", "price": None, "owner_ids": None},
        {"name": "bar", "price": 1.0, "owner_ids": None},
        {"name": "baz", "price": 2.0, "owner_ids": [1, 2, 3]},

		}
	}

	AssertObjEqual(t, pet, expect, "ID", "CreatedAt", "UpdatedAt", "DeletedAt", "UserID", "Name")

	AssertObjEqual(t, pet.Toy, expect.Toy, "ID", "CreatedAt", "UpdatedAt", "DeletedAt", "Name", "OwnerID", "OwnerType")

	if expect.Toy.Name != "" && expect.Toy.OwnerType != "pets" {
		t.Errorf("toys's OwnerType, expect: %v, got %v", "pets", expect.Toy.OwnerType)
	}
}

//
//	type User struct {
//	  Toys []Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Pet struct {
//	  Toy Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Toy struct {
//	  OwnerID   int
//	  OwnerType string
//	}
func (schema *Schema) buildPolymorphicRelation(relation *Relationship, field *Field) {
	polymorphic := field.TagSettings["POLYMORPHIC"]

	relation.Polymorphic = &Polymorphic{

		}
	case schema.Many2Many:
		joinModel := reflect.New(rel.JoinTable.ModelType).Interface()
		joinDB := base.Session(&Session{NewDB: true, Context: ctx}).Model(joinModel)

		// EXISTS owners: owners.pk = join.owner_fk for all owner refs
		ownersExists := base.Session(&Session{NewDB: true, Context: ctx}).Table(rel.Schema.Table).Select("1")
		for _, ref := range rel.References {
			if ref.OwnPrimaryKey && ref.PrimaryKey != nil {

For example, if you have an app like this:

```Python
from fastapi import FastAPI
from pydantic import BaseModel

class Item(BaseModel):
    name: str
    price: Optional[float] = None
    owner_ids: Optional[List[int]] = None

app = FastAPI()

@app.get("/items/invalidnone", response_model=Item)
def get_invalid_none():
    return None
```