* the table lacks a mapping for a given row and column, the corresponding array element is null.
   *
   * <p>Subsequent table changes will not modify the array, and vice versa.
   *
   * @param valueClass class of values stored in the returned array
   */
  @GwtIncompatible // reflection
  public @Nullable V[][] toArray(Class<V> valueClass) {

						dbName = f.DBName
					}
				}

				if tx.Statement.Distinct {
					expr = clause.Expr{SQL: "COUNT(DISTINCT(?))", Vars: []interface{}{clause.Column{Name: dbName}}}
				} else if dbName != "*" {
					expr = clause.Expr{SQL: "COUNT(?)", Vars: []interface{}{clause.Column{Name: dbName}}}
				}
			}
		}

		tx.Statement.AddClause(clause.Select{Expression: expr})
	}

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

///

### 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),

	}

	references := make([]interface{}, 0, len(constraint.References))
	for _, field := range constraint.References {
		references = append(references, clause.Column{Name: field.DBName})
	}
	vars = append(vars, clause.Table{Name: constraint.Name}, foreignKeys, clause.Table{Name: constraint.ReferenceSchema.Table}, references)
	return
}

func (rel *Relationship) ParseConstraint() *Constraint {

     * 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();

	}
	validKeys = append(validKeys, Comment)

	subSysEnvVars := env.List(fmt.Sprintf("%s%s", EnvPrefix, strings.ToUpper(subSys)))

	// Set of env vars for the sub-system to validate.
	candidates := set.CreateStringSet(subSysEnvVars...)

	// Remove all default target env vars from the candidates set (as they
	// are valid).
	for _, param := range validKeys {
		paramEnvName := getEnvVarName(subSys, Default, param)

   * 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