Bir virtual environment oluşturmak için, Python ile birlikte gelen `venv` modülünü kullanabilirsiniz.

<div class="termy">

```console
$ python -m venv .venv
```

</div>

/// details | Bu komut ne anlama geliyor

* `python`: `python` adlı programı kullan
* `-m`: bir modülü script gibi çalıştır; bir sonraki kısımda hangi modül olduğunu söyleyeceğiz
* `venv`: normalde Python ile birlikte kurulu gelen `venv` modülünü kullan

commons: CommonQueryParams ...
```

////

...**FastAPI** için özel bir anlam taşımaz. FastAPI bunu veri dönüştürme, doğrulama vb. için kullanmaz (çünkü bunlar için `Depends(CommonQueryParams)` kullanıyor).

Hatta şunu bile yazabilirsiniz:

//// tab | Python 3.10+

```Python
commons: Annotated[Any, Depends(CommonQueryParams)]
```

////

//// tab | Python 3.10+ Annotated Olmadan

/// tip | İpucu

```console
$ <font color="#4E9A06">fastapi</font> dev

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting development server 🚀

             Searching for package file structure from directories with
             <font color="#3465A4">__init__.py</font> files
             Importing from <font color="#75507B">/home/user/code/</font><font color="#AD7FA8">awesomeapp</font>

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting production server 🚀

             Searching for package file structure from directories
             with <font color="#3465A4">__init__.py</font> files
             Importing from <font color="#75507B">/home/user/code/</font><font color="#AD7FA8">awesomeapp</font>

/*
 * Copyright (C) 2016 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

        this.data = data.clone();
        this.file = null;
    }

    /**
     * Constructs a ContentCache with the given file.
     *
     * @param file the file containing the content
     * @throws IllegalArgumentException if file is null
     */
    public ContentCache(final File file) {
        if (file == null) {
            throw new IllegalArgumentException("file must not be null");
        }

application/zip                zip jar          # ZIP Compressed File
audio/basic                    au snd           # Audio Sound File
audio/x-aiff                   aif aiff aifc    # AIFF Sound File
audio/x-midi                   mid              # MIDI Sound File
audio/x-pn-realaudio           ra ram rm rpm    # REALAUDIO Sound File
audio/x-wav                    wav              # WAV Sound File
audio/x-mpegurl                mp3              # MP3 Sound File

                fp = 0L;
            }
        }
        if (file instanceof SmbNamedPipe && file.unc.startsWith("\\pipe\\")) {
            file.unc = file.unc.substring(5);
            file.send(new TransWaitNamedPipe("\\pipe" + file.unc), new TransWaitNamedPipeResponse());
        }
        file.open(openFlags, access | SmbConstants.FILE_WRITE_DATA, SmbFile.ATTR_NORMAL, 0);

                final File file = super.getFile();
                if (file != null) {
                    try {
                        Files.deleteIfExists(file.toPath());
                    } catch (final IOException e) {
                        // Log the error but don't throw to avoid masking exceptions from the main operation

        for (int i = 1; i <= 10; i++) {
            final File file = new File(dir, "file" + count + "-" + i + ".html");
            file.deleteOnExit();
            FileUtil.writeBytes(file.getAbsolutePath(), content.getBytes("UTF-8"));
            final File childDir = new File(dir, "dir" + count + "-" + i);
            childDir.mkdirs();
            generateContents(childDir, count - 1);
        }
    }