## Program and Process

We will talk a lot about the running "**process**", so it's useful to have clarity about what it means, and what's the difference with the word "**program**".

### What is a Program

The word **program** is commonly used to describe many things:

* The **code** that you write, the **Python files**.

  // `lastTransitionTime` is the last time the condition transitioned from one status to another.
  optional k8s.io.apimachinery.pkg.apis.meta.v1.Time lastTransitionTime = 3;

  // `reason` is a unique, one-word, CamelCase reason for the condition's last transition.
  optional string reason = 4;

  // `message` is a human-readable message indicating details about last transition.
  optional string message = 5;
}

  // `lastTransitionTime` is the last time the condition transitioned from one status to another.
  optional k8s.io.apimachinery.pkg.apis.meta.v1.Time lastTransitionTime = 3;

  // `reason` is a unique, one-word, CamelCase reason for the condition's last transition.
  optional string reason = 4;

  // `message` is a human-readable message indicating details about last transition.
  optional string message = 5;
}

```Python hl_lines="7"
{!../../../docs_src/path_params_numeric_validations/tutorial003.py!}
```

* 🚨 Avoid using `Optional[SomeType]`
* Instead ✨ **use `Union[SomeType, None]`** ✨.

Both are equivalent and underneath they are the same, but I would recommend `Union` instead of `Optional` because the word "**optional**" would seem to imply that the value is optional, and it actually means "it can be `None`", even if it's not optional and is still required.

I think `Union[SomeType, None]` is more explicit about what it means.

pkg image/png, type EncoderBufferPool interface, Put(*EncoderBuffer)
pkg math/big, method (*Int) IsInt64() bool
pkg math/big, method (*Int) IsUint64() bool
pkg math/big, type Word uint
pkg math/bits (darwin-amd64), const UintSize = 64
pkg math/bits (darwin-amd64-cgo), const UintSize = 64
pkg math/bits (freebsd-386), const UintSize = 32
pkg math/bits (freebsd-386-cgo), const UintSize = 32

### Preprocess the OpenAPI Specification for the Client Generator

The generated code still has some **duplicated information**.

We already know that this method is related to the **items** because that word is in the `ItemsService` (taken from the tag), but we still have the tag name prefixed in the method name too. 😕

We will probably still want to keep it for OpenAPI in general, as that will ensure that the operation IDs are **unique**.

* In lines starting with `===` or `!!!`, translate only the ` "... Text ..."` part. Leave the rest unchanged.

* You can translate info boxes like `!!! warning` with for example `!!! warning "Achtung"`. But do not change the word immediately after the `!!!`, it determines the color of the info box.

* Do not change the paths in links to images, code files, Markdown documents.

    top-level class and `Credential` is replaced with a utility class called
    `Credentials`.

 *  **OkHttpClient.getFollowProtocolRedirects() renamed to
    getFollowSslRedirects()**. We reserve the word _protocol_ for the HTTP
    version being used (HTTP/1.1, HTTP/2). The old name of this method was
    misleading; it was always used to configure redirects between `https://` and
    `http://` schemes.

file: org.apache.spark.rdd.RDD[String] = s3a://testbucket/testdata MapPartitionsRDD[1] at textFile at <console>:24

scala> val counts = file.flatMap(line => line.split(" ")).map(word => (word, 1)).reduceByKey(_ + _)
counts: org.apache.spark.rdd.RDD[(String, Int)] = ShuffledRDD[4] at reduceByKey at <console>:25

scala> counts.saveAsTextFile("s3a://testbucket/wordcount")
```