from pydantic import BaseModel, Field, ValidationError

from .utils import needs_pydanticv1, needs_pydanticv2


class Person:
    def __init__(self, name: str):
        self.name = name


class Pet:
    def __init__(self, owner: Person, name: str):
        self.owner = owner
        self.name = name


@dataclass
class Item:
    name: str
    count: int

    # Settings management
    "pydantic-settings >=2.0.0",
    # Extra Pydantic data types
    "pydantic-extra-types >=2.0.0",
]

[tool.pdm]
version = { source = "file", path = "fastapi/__init__.py" }
distribution = true

[tool.pdm.build]
source-includes = [
    "tests/",
    "docs_src/",
    "requirements*.txt",
    "scripts/",
    # For a test
    "docs/en/docs/img/favicon.png",

```

then it is a "callable".

## 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`.

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

 ╭─ <font color="#8AE234"><b>Python module file</b></font> ─╮

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

 ╭─ <font color="#8AE234"><b>Python module file</b></font> ─╮

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

 ╭─ <font color="#8AE234"><b>Python module file</b></font> ─╮

🌅 📟 🤙 🎏.

, 👥 🔜 🎯 🕴 🔛 🔺.

## 📁 📊

➡️ 💬 👆 ✔️ 📁 📛 `my_super_project` 👈 🔌 🎧-📁 🤙 `sql_app` ⏮️ 📊 💖 👉:

```
.
└── sql_app
    ├── __init__.py
    ├── crud.py
    ├── database.py
    ├── main.py
    └── schemas.py
```

👉 🌖 🎏 📊 👥 ✔️ 🇸🇲 🔰.

🔜 ➡️ 👀 ⚫️❔ 🔠 📁/🕹 🔨.

## ✍ 🏒 🍕

➡️ 🔗 📁 `sql_app/database.py`.

## 📁 📊

👫 🖼, ➡️ 💬 👆 ✔️ 📁 📛 `my_super_project` 👈 🔌 🎧-📁 🤙 `sql_app` ⏮️ 📊 💖 👉:

```
.
└── sql_app
    ├── __init__.py
    ├── crud.py
    ├── database.py
    ├── main.py
    ├── models.py
    └── schemas.py
```

📁 `__init__.py` 🛁 📁, ✋️ ⚫️ 💬 🐍 👈 `sql_app` ⏮️ 🌐 🚮 🕹 (🐍 📁) 📦.

🔜 ➡️ 👀 ⚫️❔ 🔠 📁/🕹 🔨.

## ❎ `SQLAlchemy`

🥇 👆 💪 ❎ `SQLAlchemy`:

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

 ╭─ <font color="#8AE234"><b>Python module file</b></font> ─╮

```
.
└── sql_app
    ├── __init__.py
    ├── crud.py
    ├── database.py
    ├── main.py
    ├── models.py
    └── schemas.py
```

The file `__init__.py` is just an empty file, but it tells Python that `sql_app` with all its modules (Python files) is a package.

Now let's see what each file/module does.