///

## Types and validation { #types-and-validation }

These environment variables can only handle text strings, as they are external to Python and have to be compatible with other programs and the rest of the system (and even with different operating systems, as Linux, Windows, macOS).

# Separate OpenAPI Schemas for Input and Output or Not { #separate-openapi-schemas-for-input-and-output-or-not }

Since **Pydantic v2** was released, the generated OpenAPI is a bit more exact and **correct** than before. 😎

In fact, in some cases, it will even have **two JSON Schemas** in OpenAPI for the same Pydantic model, for input and output, depending on if they have **default values**.

Let's see how that works and how to change it if you need to do that.

      <description>
        This is the file specification used to activate a profile. The missing value will be the location
        of a file that needs to exist, and if it doesn't the profile must run.  On the other hand exists will test
        for the existence of the file and if it is there will run the profile.
      </description>
      <fields>
        <field>
          <name>missing</name>
          <version>1.0.0+</version>

[project.optional-dependencies]

standard = [
    "fastapi-cli[standard] >=0.0.8",
    # For the test client
    "httpx >=0.23.0,<1.0.0",
    # For templates
    "jinja2 >=3.1.5",
    # For forms and file uploads
    "python-multipart >=0.0.18",
    # To validate email fields
    "email-validator >=2.0.0",
    # Uvicorn with uvloop
    "uvicorn[standard] >=0.12.0",
    # # Settings management

 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package okhttp3

import java.util.concurrent.TimeUnit
import okhttp3.internal.concurrent.TaskRunner
import okhttp3.internal.connection.ConnectionListener
import okhttp3.internal.connection.RealConnectionPool

/**
 * Manages reuse of HTTP and HTTP/2 connections for reduced network latency. HTTP requests that

 * provides {@code static final} constants, so the test suite focuses on
 * value correctness, bit‑mask logic, and some derived properties.
 *
 * <p>Mockito is exercised in a dummy scenario to satisfy the
 * request for an interaction test.  The mock represents a
 * {@code SmbTransport} collaborator and is used only for
 * demonstration – the real class behaviour is not required for
 * validating constants.
 */

**FastAPI** uses them internally to achieve this.

///

## Dependencies with `yield` and `HTTPException` { #dependencies-with-yield-and-httpexception }

You saw that you can use dependencies with `yield` and have `try` blocks that try to execute some code and then run some exit code after `finally`.

You can also use `except` to catch the exception that was raised and do something with it.

		desc. If you want to find documents which has "Fess" and sort them in
		descending order, you can enter:
		<pre>Fess sort:content_length.desc</pre>
		The available sort field are "created", "content_length" and
		"last_modified", and they are customizable.
	</dd>
	<dt>AND</dt>
	<dd>
		AND operator is the default conjunction operator. You can omit it from
		a query. AND operator matches documents where both terms exist

#### Tuple and Set { #tuple-and-set }

You would do the same to declare `tuple`s and `set`s:

{* ../../docs_src/python_types/tutorial007_py39.py hl[1] *}

This means:

* The variable `items_t` is a `tuple` with 3 items, an `int`, another `int`, and a `str`.
* The variable `items_s` is a `set`, and each of its items is of type `bytes`.

#### Dict { #dict }

and what the program that uses the Library does.

  1. You may copy and distribute verbatim copies of the Library's
complete source code as you receive it, in any medium, provided that
you conspicuously and appropriately publish on each copy an
appropriate copyright notice and disclaimer of warranty; keep intact
all the notices that refer to this License and to the absence of any