**Example**

                ```python
                from fastapi import FastAPI

                app = FastAPI(
                    servers=[
                        {"url": "https://stag.example.com", "description": "Staging environment"},
                        {"url": "https://prod.example.com", "description": "Production environment"},
                    ]

////

## Read env vars in Python { #read-env-vars-in-python }

You could also create environment variables **outside** of Python, in the terminal (or with any other method), and then **read them in Python**.

For example you could have a file `main.py` with:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip

    @Mock
    private CredentialsInternal credentialsInternal;
    @Mock
    private SmbTransportImpl transport;

    private SmbSessionImpl newSession() {
        return new SmbSessionImpl(cifsContext, "server.example", "EXAMPLE", transport);
    }

    @BeforeEach
    void setup() {
        // Base context configuration - always needed
        when(cifsContext.getConfig()).thenReturn(configuration);

async def update_item(
    *,
    item_id: int,
    item: Annotated[
        Item,
        Body(
            openapi_examples={
                "normal": {
                    "summary": "A normal example",
                    "description": "A **normal** item works correctly.",
                    "value": {
                        "name": "Foo",
                        "description": "A very nice Item",

### 3. Example

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

/// danger

This is an "advanced" feature.

If you are just starting with **FastAPI** you might want to skip this section.

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * Annotates a "top-level" type-variable usage that takes its nullness from the type argument
 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * Annotates a "top-level" type-variable usage that takes its nullness from the type argument
 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.

    private ReserializedCollectionGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen) {
      this.gen = gen;
    }

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override
    public Collection<E> create(Object... elements) {
      return SerializableTester.reserialize(gen.create(elements));
    }

    @Override

           --set=decision_logs.console=true
```

### 2. Create a sample OPA Policy

In another terminal, create a policy that allows root user all access and for all other users denies `PutObject`:

```sh
cat > example.rego <<EOF
package httpapi.authz

import input

default allow = false

# Allow the root user to perform any action.
allow {
 input.owner == true
}