Variáveis de ambiente podem ser úteis para lidar com **configurações** do aplicativo, como parte da **instalação** do Python, etc.

## Criar e Usar Variáveis de Ambiente { #create-and-use-env-vars }

Você pode **criar** e usar variáveis de ambiente no **shell (terminal)**, sem precisar do Python:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console

# ----------------------------------------------------------------------------
# Apache Maven Wrapper startup batch script, version 3.3.2
#
# Required ENV vars:
# ------------------
#   JAVA_HOME - location of a JDK home dir
#
# Optional ENV vars
# -----------------
#   MAVEN_OPTS - parameters passed to the Java VM when running Maven
#     e.g. to debug Maven itself, use

     * clone. The only requirement is that invocations of {@link #addRepository(Repository)} on the clone do not affect
     * the state of the original resolver and vice versa.
     *
     * @return The cloned resolver, never {@code null}.
     */
    ModelResolver newCopy();

///

### Pydantic v1 and v2 on the same app { #pydantic-v1-and-v2-on-the-same-app }

It's **not supported** by Pydantic to have a model of Pydantic v2 with its own fields defined as Pydantic v1 models or vice versa.

```mermaid
graph TB
    subgraph "❌ Not Supported"
        direction TB
        subgraph V2["Pydantic v2 Model"]
            V1Field["Pydantic v1 Model"]
        end
        subgraph V1["Pydantic v1 Model"]

func newContext(r *http.Request, w http.ResponseWriter, api string) context.Context {
	reqID := w.Header().Get(xhttp.AmzRequestID)

	vars := mux.Vars(r)
	bucket := vars["bucket"]
	object := likelyUnescapeGeneric(vars["object"], url.PathUnescape)
	reqInfo := &logger.ReqInfo{
		DeploymentID: globalDeploymentID(),
		RequestID:    reqID,
		RemoteHost:   handlers.GetSourceIP(r),

@REM ----------------------------------------------------------------------------
@REM Apache Maven Wrapper startup batch script, version 3.3.4
@REM
@REM Optional ENV vars
@REM   MVNW_REPOURL - repo url base for downloading maven distribution
@REM   MVNW_USERNAME/MVNW_PASSWORD - user and password for downloading maven
@REM   MVNW_VERBOSE - true: enable verbose log; others: silence the output

///

### Pydantic v1 e v2 na mesma aplicação { #pydantic-v1-and-v2-on-the-same-app }

Não é suportado pelo Pydantic ter um modelo do Pydantic v2 com campos próprios definidos como modelos do Pydantic v1, ou vice-versa.

```mermaid
graph TB
    subgraph "❌ Not Supported"
        direction TB
        subgraph V2["Pydantic v2 Model"]
            V1Field["Pydantic v1 Model"]
        end
        subgraph V1["Pydantic v1 Model"]

   */
  public abstract double transform(double x);

  /**
   * Returns the inverse linear transformation. The inverse of a horizontal transformation is a
   * vertical transformation, and vice versa. The inverse of the {@link #forNaN} transformation is
   * itself. In all other cases, the inverse is a transformation such that applying both the

    source "./ci/official/envs/$env_file"
  done
  set -u
  echo '==TFCI==: Evaluated the following TFCI variables from $TFCI:'
  export -p | grep TFCI

  # Load those stored pre-existing TFCI_ vars, if any
  if [[ -s "$FROM_ENV" ]]; then
    echo '==TFCI==: NOTE: Loading the following env parameters, which were'
    echo 'already set in the shell environment. If you want to disable this'

   * have the provided key, an empty collection is returned.
   *
   * <p>Changes to the returned collection will update the underlying multimap, and vice versa.
   *
   * <p>Because a {@code SortedSetMultimap} has unique sorted values for a given key, this method
   * returns a {@link SortedSet}, instead of the {@link java.util.Collection} specified in the