* Und die Datei `app/internal/admin.py` ist ein weiteres Submodul: `app.internal.admin`.

<img src="/img/tutorial/bigger-applications/package.svg">

Die gleiche Dateistruktur mit Kommentaren:

```
.
├── app                  # „app“ ist ein Python-Package
│   ├── __init__.py      # diese Datei macht „app“ zu einem „Python-Package“

# Bigger Applications - Multiple Files

If you are building an application or a web API, it's rarely the case that you can put everything on a single file.

**FastAPI** provides a convenience tool to structure your application while keeping all the flexibility.

!!! info
    If you come from Flask, this would be the equivalent of Flask's Blueprints.

## An example file structure

Let's say you have a file structure like this:

```
.
├── app

* 📤 📁 `app/internal/` ⏮️ ➕1️⃣ 📁 `__init__.py`, ⚫️ ➕1️⃣ "🐍 📦": `app.internal`.
*  & 📁 `app/internal/admin.py` ➕1️⃣ 🔁: `app.internal.admin`.

<img src="/img/tutorial/bigger-applications/package.svg">

🎏 📁 📊 ⏮️ 🏤:

```
.
├── app                  # "app" is a Python package
│   ├── __init__.py      # this file makes "app" a "Python package"

* 还有一个子目录 `app/internal/` 包含另一个 `__init__.py` 文件，因此它是又一个「Python 子包」：`app.internal`。
* `app/internal/admin.py` 是另一个子模块：`app.internal.admin`。

<img src="https://fastapi.tiangolo.com/img/tutorial/bigger-applications/package.svg">

带有注释的同一文件结构：

```
.
├── app                  # 「app」是一个 Python 包
│   ├── __init__.py      # 这个文件使「app」成为一个 Python 包
│   ├── main.py          # 「main」模块，例如 import app.main

	Children []Child
	ChildPtr *Child
	ChildToEmbed
}

const (
	emptyXML = `
<Parent>
    <I></I>
    <IPtr></IPtr>
    <Is></Is>
    <IPtrs></IPtrs>
    <F></F>
    <FPtr></FPtr>
    <Fs></Fs>
    <FPtrs></FPtrs>
    <B></B>
    <BPtr></BPtr>
    <Bs></Bs>
    <BPtrs></BPtrs>
    <Bytes></Bytes>
    <BytesPtr></BytesPtr>
    <S></S>
    <SPtr></SPtr>
    <Ss></Ss>

					var (
						rValLen   = db.Statement.ReflectValue.Len()
						objs      = make([]reflect.Value, 0, rValLen)
						fieldType = rel.Field.FieldType
						isPtr     = fieldType.Kind() == reflect.Ptr
					)

					if !isPtr {
						fieldType = reflect.PtrTo(fieldType)
					}

					elems := reflect.MakeSlice(reflect.SliceOf(fieldType), 0, 10)

	"runtime.gcWriteBarrier5": {Results: []byte{I64}},                                     // -> bufptr
	"runtime.gcWriteBarrier6": {Results: []byte{I64}},                                     // -> bufptr
	"runtime.gcWriteBarrier7": {Results: []byte{I64}},                                     // -> bufptr
	"runtime.gcWriteBarrier8": {Results: []byte{I64}},                                     // -> bufptr

		nif.Cond = ir.NewLogicalExpr(base.Pos, ir.OOROR, overflow, memCond)
		nifPtr := ir.NewIfStmt(base.Pos, nil, nil, nil)
		nifPtr.Cond = ir.NewBinaryExpr(base.Pos, ir.OEQ, unsafePtr, typecheck.NodNil())
		nifPtr.Body.Append(mkcall("panicunsafeslicenilptr", nil, &nifPtr.Body))
		nif.Body.Append(nifPtr, mkcall("panicunsafeslicelen", nil, &nif.Body))
		appendWalkStmt(init, nif)
	}

		bz2.c[b]++
		bufIndex++
	}

	if origPtr >= uint(bufIndex) {
		return StructuralError("origPtr out of bounds")
	}

	// We have completed the entropy decoding. Now we can perform the
	// inverse BWT and setup the RLE buffer.
	bz2.preRLE = bz2.tt[:bufIndex]
	bz2.preRLEUsed = 0
	bz2.tPos = inverseBWT(bz2.preRLE, origPtr, bz2.c[:])
	bz2.lastByte = -1
	bz2.byteRepeats = 0
	bz2.repeats = 0

			Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil),
			Goto("checkPtr")),
		Bloc("checkPtr",
			Valu("ptr1", OpLoad, ptrType, 0, nil, "sb", "mem"),
			Valu("nilptr", OpConstNil, ptrType, 0, nil),
			Valu("bool1", OpNeqPtr, c.config.Types.Bool, 0, nil, "ptr1", "nilptr"),
			If("bool1", "secondCheck", "exit")),
		Bloc("secondCheck",
			Valu("bool2", OpIsNonNil, c.config.Types.Bool, 0, nil, "ptr1"),
			If("bool2", "extra", "exit")),