sha256sum := ""
	var opts ObjectOptions
	// Iterating over creatPartCases to generate multipart chunks.
	for _, part := range parts {
		_, err = obj.PutObjectPart(context.Background(), part.bucketName, part.objName, part.uploadID, part.PartID, mustGetPutObjReader(t, bytes.NewBufferString(part.inputReaderData), part.inputDataSize, part.inputMd5, sha256sum), opts)
		if err != nil {
			t.Fatalf("%s : %s", instanceType, err)
		}
	}

		Recursive: false,
		Immediate: false,
	})
	if err != nil {
		t.Errorf("Failure during deleting part.1 - %v", err)
	}

	err = firstDisk.WriteAll(context.Background(), bucket, pathJoin(object, fi.DataDir, "part.1"), []byte{})
	if err != nil {
		t.Errorf("Failure during creating part.1 - %v", err)
	}

	ModTime    time.Time         `json:"modTime" msg:"mt"`    // Date and time at which the part was uploaded.
	Index      []byte            `json:"index,omitempty" msg:"i,omitempty"`
	Checksums  map[string]string `json:"crc,omitempty" msg:"crc,omitempty"`   // Content Checksums
	Error      string            `json:"error,omitempty" msg:"err,omitempty"` // only set while reading part meta from drive.
}

			res = make([]map[string]string, parts)
		}
		b = b[n:]
		for part := 0; part < int(parts); part++ {
			if len(b) < length {
				break
			}
			// Read part checksum
			cs := base64.StdEncoding.EncodeToString(b[:length])
			b = b[length:]
			if res[part] == nil {
				res[part] = make(map[string]string, 1)
			}
			res[part][typ.String()] = cs
		}
	}
	return res
}

			t.Errorf("Test %d: ServerSideEncryptionKDF must be part of metadata: %v", i, kdf)
		}
		if iv, ok := test.metadata[crypto.MetaIV]; !ok {
			t.Errorf("Test %d: crypto.SSEIV must be part of metadata: %v", i, iv)
		}
		if mac, ok := test.metadata[crypto.MetaSealedKeySSEC]; !ok {
			t.Errorf("Test %d: ServerSideEncryptionKeyMAC must be part of metadata: %v", i, mac)
		}
	}
}

					otherPart := getPartNum(other[0])
					if part != otherPart {
						fmt.Println("part ", part, " != other part", otherPart, other[0])
						continue
					}
					// fmt.Println("part ", part, "other part", otherPart, other[0])
					fmt.Printf("Reading version %q Part %d.\n", otherKey, otherPart)
					// os.Exit(0)
					otherM, err := readAndMap(other, part, block)
					if err != nil {
						fmt.Println(err)

And that function takes parameters in the same way that *path operation functions* do.

/// tip

You'll see what other "things", apart from functions, can be used as dependencies in the next chapter.

///

Whenever a new request arrives, **FastAPI** will take care of:

* Calling your dependency ("dependable") function with the correct parameters.

Using an option directly from Starlette you can declare a *path parameter* containing a *path* using a URL like:

```
/files/{file_path:path}
```

In this case, the name of the parameter is `file_path`, and the last part, `:path`, tells it that the parameter should match any *path*.

So, you can use it with:

```Python hl_lines="6"
{!../../docs_src/path_params/tutorial004.py!}
```

/// tip

	listPartsResponse.Parts = make([]Part, len(partsInfo.Parts))
	for index, part := range partsInfo.Parts {
		newPart := Part{}
		newPart.PartNumber = part.PartNumber
		newPart.ETag = "\"" + part.ETag + "\""
		newPart.Size = part.Size
		newPart.LastModified = amztime.ISO8601Format(part.LastModified.UTC())
		newPart.ChecksumCRC32 = part.ChecksumCRC32
		newPart.ChecksumCRC32C = part.ChecksumCRC32C

{* ../../docs_src/events/tutorial003.py hl[14:19] *}

The first part of the function, before the `yield`, will be executed **before** the application starts.

And the part after the `yield` will be executed **after** the application has finished.

### Async Context Manager

If you check, the function is decorated with an `@asynccontextmanager`.