price: float
    tax: float | None = None
    tags: set[str] = set()


@app.post(
    "/items/",
    response_model=Item,
    summary="Create an item",
    response_description="The created item",
)
async def create_item(item: Item):
    """
    Create an item with all the information:

    - **name**: each item must have a name
    - **description**: a long description
    - **price**: required

                    },
                    "summary": "Create an item",
                    "description": "Create an item with all the information:\n\n- **name**: each item must have a name\n- **description**: a long description\n- **price**: required\n- **tax**: if the item doesn't have tax, you can omit this\n- **tags**: a set of unique tag strings for this item",
                    "operationId": "create_item_items__post",
                    "requestBody": {

                    },
                    "summary": "Create an item",
                    "description": "Create an item with all the information:\n\n- **name**: each item must have a name\n- **description**: a long description\n- **price**: required\n- **tax**: if the item doesn't have tax, you can omit this\n- **tags**: a set of unique tag strings for this item",
                    "operationId": "create_item_items__post",
                    "requestBody": {

              },
              "changes-requested": {
                "delay": 2628000,
                "message": "As this PR had requested changes to be applied but has been inactive for a while, it's now going to be closed. But if there's anyone interested, feel free to create a new PR."
              }

### Create a dependency

Now use the `SessionLocal` class we created in the `sql_app/database.py` file to create a dependency.

We need to have an independent database session/connection (`SessionLocal`) per request, use the same session through all the request and then close it after the request is finished.

And then a new session will be created for the next request.

You can also create an environment variable only for a specific program invocation, that is only available to that program, and only for its duration.

To do that, create it right before the program itself, on the same line:

<div class="termy">

```console
// Create an env var MY_NAME in line for this program call
$ MY_NAME="Wade Wilson" python main.py

```console
$ pip install jinja2

---> 100%
```

</div>

## Using `Jinja2Templates`

* Import `Jinja2Templates`.
* Create a `templates` object that you can re-use later.
* Declare a `Request` parameter in the *path operation* that will return a template.

    contents = f.read()
    print(contents)
```

Underneath, the `open("./somefile.txt")` creates an object that is called a "Context Manager".

When the `with` block finishes, it makes sure to close the file, even if there were exceptions.

When you create a dependency with `yield`, **FastAPI** will internally create a context manager for it, and combine it with some other related tools.

## Classes as dependencies

You might notice that to create an instance of a Python class, you use that same syntax.

For example:

```Python
class Cat:
    def __init__(self, name: str):
        self.name = name


fluffy = Cat(name="Mr Fluffy")
```

In this case, `fluffy` is an instance of the class `Cat`.

And to create `fluffy`, you are "calling" `Cat`.

        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/files/": {
                "post": {
                    "summary": "Create File",
                    "operationId": "create_file_files__post",
                    "requestBody": {
                        "content": {
                            "multipart/form-data": {
                                "schema": IsDict(