* <p>
 * Model transformers allow plugins and extensions to modify the POM model during the build process.
 * Transformations can be applied at three different stages:
 * <ol>
 *   <li>File model - The raw model as read directly from the file</li>
 *   <li>Raw model - The model after inheritance has been applied</li>

 * <li>Settings: the {@code settings.xml} can be used to provide additional repositories in the three level of settings (user, project, installation).</li>
 * </ol>

 * <li>Settings: the {@code settings.xml} can be used to provide additional repositories in the three level of settings (user, project, installation).</li>
 * </ol>

			default:
				// There was error in the REST request, retry after sometime as probably the peer is down.
				time.Sleep(5 * time.Second)
			}
		}
	}()
}

// Trace - send http trace request to peer nodes
func (client *peerRESTClient) Trace(ctx context.Context, traceCh chan<- []byte, traceOpts madmin.ServiceTraceOpts) {
	go func() {
		for {
			// Blocks until context is canceled or an error occurs.

		if err != nil {
			return nil, err
		}
		fn := filepath.Join(dirPath, "trace.out")
		f, err := Create(fn)
		if err != nil {
			return nil, err
		}
		err = trace.Start(f)
		if err != nil {
			return nil, err
		}
		prof.ext = "trace"
		prof.stopFn = func() ([]byte, error) {
			trace.Stop()
			err := f.Close()
			if err != nil {
				return nil, err
			}

```Python hl_lines="4  9-12  25-27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):

```Python hl_lines="4  9-12  25-27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):

```Python hl_lines="4  9-12  25-27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):

```Python hl_lines="4  9-12  25-27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):

    "description": "The bartenders",
    "price": 62,
    "tax": 20.2
}
```

serán incluidos en el response.

#### Datos con los mismos valores que los valores por defecto

Si los datos tienen los mismos valores que los valores por defecto, como el artículo con ID `baz`:

```Python hl_lines="3  5-6"
{
    "name": "Baz",
    "description": None,
    "price": 50.2,
    "tax": 10.5,
    "tags": []