```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">

* 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">

  @GwtIncompatible // different overflow behavior; could probably be made to work by using ~~
  public void testConcat_overflow_negative() {
    int dim1 = 1 << 16;
    int dim2 = 1 << 15;
    assertThat(dim1 * dim2).isLessThan(0);
    testConcatOverflow(dim1, dim2);
  }

  @GwtIncompatible // different overflow behavior; could probably be made to work by using ~~
  public void testConcat_overflow_nonNegative() {

The **default** value of the **function parameter** is the **actual default** value, that's more intuitive with Python in general. 😌

You could **call** that same function in **other places** without FastAPI, and it would **work as expected**. If there's a **required** parameter (without a default value), your **editor** will let you know with an error, **Python** will also complain if you run it without passing the required parameter.

	// S3 also supports the older SelectObjectContentRequest tag,
	// though it is no longer found in documentation. This is
	// checked and renamed below to allow older clients to also
	// work.
	if start.Name.Local == legacyXMLName {
		start.Name = xml.Name{Space: "", Local: "SelectRequest"}
	}

	// Make subtype to avoid recursive UnmarshalXML().
	type subS3Select S3Select

        source = Buffer(),
      )

    assertFailsWith<EOFException> {
      parts.nextPart()
    }
  }

  /** Confirm that [MultipartBody] and [MultipartReader] can work together. */
  @Test fun `multipart round trip`() {
    val body =
      MultipartBody.Builder("boundary")
        .setType(MultipartBody.PARALLEL)
        .addPart("Quick".toRequestBody("text/plain".toMediaType()))

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 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
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/*
 * Licensed to the Apache Software Foundation (ASF) under one
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 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
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