### ایجاد کنید
* فایلی به نام `main.py` با محتوای زیر ایجاد کنید:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

cases section below.

To access a struct, union, or enum type directly, prefix it with
struct_, union_, or enum_, as in C.struct_stat. The size of any C type
T is available as C.sizeof_T, as in C.sizeof_struct_stat. These
special prefixes means that there is no way to directly reference a C
identifier that starts with "struct_", "union_", "enum_", or
"sizeof_", such as a function named "struct_function".

  // well-known group names.
  // Required.
  optional string name = 1;
}

// LimitResponse defines how to handle requests that can not be executed right now.
// +union
message LimitResponse {
  // `type` is "Queue" or "Reject".
  // "Queue" means that requests that can not be executed upon arrival
  // are held in a queue until they can be executed or a queuing limit
  // is reached.

}
```

🔄, ⚫️ 🔜 🗜 📊 🆎, ✔, 📄, ♒️.

## 💗 💪 = & 🔢

↗️, 👆 💪 📣 🌖 🔢 🔢 🕐❔ 👆 💪, 🌖 🙆 💪 🔢.

, 🔢, ⭐ 💲 🔬 🔢 🔢, 👆 🚫 ✔️ 🎯 🚮 `Query`, 👆 💪:

```Python
q: Union[str, None] = None
```

⚖️ 🐍 3️⃣.1️⃣0️⃣ & 🔛:

```Python
q: str | None = None
```

🖼:

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="27"

		{rulesCase4, rules2Case4, expectedResultCase4},
		{rulesCase5, rules2Case5, expectedResultCase5},
	}

	for i, testCase := range testCases {
		result := testCase.rules.Union(testCase.rules2)

		if !reflect.DeepEqual(testCase.expectedResult, result) {
			t.Fatalf("test %v: result: expected: %v, got: %v", i+1, testCase.expectedResult, result)
		}
	}
}

// E.g. it could know whether we're in eager mode or graph mode, keeps track
// of gradient tapes, etc.
typedef struct TF_ExecutionContext TF_ExecutionContext;

// A TF_AbstractTensor is an input to an operation. E.g. it could be a union
// type of eager and graph tensors. It is also the result of executing an
// operation.
typedef struct TF_AbstractTensor TF_AbstractTensor;

// A TF_AbstractOp is the metadata we need to execute an operation. E.g. this

  // well-known group names.
  // Required.
  optional string name = 1;
}

// LimitResponse defines how to handle requests that can not be executed right now.
// +union
message LimitResponse {
  // `type` is "Queue" or "Reject".
  // "Queue" means that requests that can not be executed upon arrival
  // are held in a queue until they can be executed or a queuing limit
  // is reached.

  // well-known group names.
  // Required.
  optional string name = 1;
}

// LimitResponse defines how to handle requests that can not be executed right now.
// +union
message LimitResponse {
  // `type` is "Queue" or "Reject".
  // "Queue" means that requests that can not be executed upon arrival
  // are held in a queue until they can be executed or a queuing limit
  // is reached.

Dado que, por padrão, valores singulares são interpretados como parâmetros de consulta, você não precisa explicitamente adicionar uma `Query`, você pode somente:

```Python
q: Union[str, None] = None
```

Ou como em Python 3.10 e versões superiores:

```Python
q: str | None = None
```

Por exemplo:

//// tab | Python 3.10+

```Python hl_lines="26"

  //
  // Element-level accessors
  //

  /**
   * Returns a live view of the nodes which have an incident edge in common with {@code node} in
   * this graph.
   *
   * <p>This is equal to the union of {@link #predecessors(Object)} and {@link #successors(Object)}.
   *
   * <p>If {@code node} is removed from the graph after this method is called, the {@code Set}