on the same machine by simply switching the value of `HERMETIC_PYTHON_VERSION`
between the runs. All the python-agnostic parts of the build cache from the
previous build will be preserved and reused for the subsequent builds.

### Specifying Python dependencies

During bazel build all TensorFlow's Python dependencies are pinned to their
specific versions. This is necessary to ensure reproducibility of the build.

//
// An Arena must never be used concurrently by multiple goroutines.
type Arena struct {
	a unsafe.Pointer
}

// NewArena allocates a new arena.
func NewArena() *Arena {
	return &Arena{a: runtime_arena_newArena()}
}

// Free frees the arena (and all objects allocated from the arena) so that
// memory backing the arena can be reused fairly quickly without garbage

- Temporary credentials have a limited lifetime, there is no need to rotate them or explicitly revoke them. Expired temporary credentials cannot be reused.

## Identity Federation

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[10,15] *}

### Return values { #return-values }

And they can return values or not, the values won't be used.

So, you can reuse a normal dependency (that returns a value) you already use somewhere else, and even though the value won't be used, the dependency will be executed:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[11,16] *}

```Python
from starlette.exceptions import HTTPException as StarletteHTTPException
```

### Reuse **FastAPI**'s exception handlers { #reuse-fastapis-exception-handlers }

If you want to use the exception along with the same default exception handlers from  **FastAPI**, you can import and reuse the default exception handlers from `fastapi.exception_handlers`:

{* ../../docs_src/handling_errors/tutorial006.py hl[2:5,15,21] *}

import (
	"context"
)

const (
	memTotal     = "total"
	memUsed      = "used"
	memFree      = "free"
	memBuffers   = "buffers"
	memCache     = "cache"
	memUsedPerc  = "used_perc"
	memShared    = "shared"
	memAvailable = "available"
)

var (
	memTotalMD     = NewGaugeMD(memTotal, "Total memory on the node")
	memUsedMD      = NewGaugeMD(memUsed, "Used memory on the node")

{* ../../docs_src/custom_docs_ui/tutorial001.py hl[8] *}

### Include the custom docs { #include-the-custom-docs }

Now you can create the *path operations* for the custom docs.

You can reuse FastAPI's internal functions to create the HTML pages for the docs, and pass them the needed arguments:

And it will save the returned value in a <abbr title="A utility/system to store computed/generated values, to reuse them instead of computing them again.">"cache"</abbr> and pass it to all the "dependants" that need it in that specific request, instead of calling the dependency multiple times for the same request.

	}{
		{"a b", "", "a b"},
		{"a b", "url", "a+b"},
		{"p- ", "url", "p-+"},
		{"p-%", "url", "p-%25"},
		{"p/", "url", "p/"},
		{"p/", "url", "p/"},
		{"~user", "url", "%7Euser"},
		{"*user", "url", "*user"},
		{"user+password", "url", "user%2Bpassword"},
		{"_user", "url", "_user"},
		{"firstname.lastname", "url", "firstname.lastname"},
	}
	for i, testCase := range testCases {

* Import `Jinja2Templates`.
* Create a `templates` object that you can reuse later.
* Declare a `Request` parameter in the *path operation* that will return a template.
* Use the `templates` you created to render and return a `TemplateResponse`, pass the name of the template, the request object, and a "context" dictionary with key-value pairs to be used inside of the Jinja2 template.

{* ../../docs_src/templates/tutorial001.py hl[4,11,15:18] *}