# Classes as Dependencies { #classes-as-dependencies }

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example { #a-dict-from-the-previous-example }

In the previous example, we were returning a `dict` from our dependency ("dependable"):

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

	}

	DB.Migrator().DropTable(&Post{}, &Category{}, "post_categories")
	DB.AutoMigrate(&Post{}, &Category{})

	post := Post{
		Title: "Hello World",
		Categories: []*Category{
			{Title: "Coding"},
			{Title: "Golang"},
		},
	}

	if err := DB.Create(&post).Error; err != nil {
		t.Errorf("Failed, got error: %v", err)
	}
}

func TestGaussDBOnConstraint(t *testing.T) {

import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * CompactLinkedHashSet is an implementation of a Set, which a predictable iteration order that
 * matches the insertion order. All optional operations (adding and removing) are supported. All
 * elements, including {@code null}, are permitted.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)

        "value (%s) is outside the range for an unsigned long value",
        value);
    return fromLongBits(value.longValue());
  }

  /**
   * Returns an {@code UnsignedLong} holding the value of the specified {@code String}, parsed as an
   * unsigned {@code long} value.
   *
   * @throws NumberFormatException if the string does not contain a parsable unsigned {@code long}
   *     value
   */

The `str | None` (Python 3.10+) or `Union` in `Union[str, None]` (Python 3.8+) is not used by FastAPI to determine that the value is not required, it will know it's not required because it has a default value of `= None`.

But adding the type annotations will allow your editor to give you better support and detect errors.

///

## Without Pydantic { #without-pydantic }

  <a href="https://fastapi.tiangolo.com"><img src="https://fastapi.tiangolo.com/img/logo-margin/logo-teal.png" alt="FastAPI"></a>
</p>
<p align="center">
    FastAPI, framework performa tinggi, mudah dipelajari, cepat untuk coding, siap untuk pengembangan
</p>
<p align="center">
<a href="https://github.com/fastapi/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster" target="_blank">

#include "tensorflow/core/graph/graph.h"
#include "tensorflow/core/graph/node_builder.h"
#include "tensorflow/core/graph/validate.h"
#include "tensorflow/core/lib/gtl/array_slice.h"
#include "tensorflow/core/platform/coding.h"
#include "tensorflow/core/platform/errors.h"
#include "tensorflow/core/platform/mem.h"
#include "tensorflow/core/platform/mutex.h"
#include "tensorflow/core/platform/protobuf.h"
#include "tensorflow/core/platform/status.h"

    class DoShareEnumValidation {

        static Stream<Arguments> invalidShareEnumCases() {
            return Stream.of(
                    // Missing trailing slash -> should complain about directory ending
                    Arguments.of("smb://server/share", "/share", true),
                    // Not a server root -> invalid list operation
                    Arguments.of("smb://server/share/", "/share/", false));
        }

        // Then
        assertNotNull(exception.getContext());
        assertTrue(exception.getContext().isEmpty());

        // Adding null context should be safe
        exception.withContext(null);
        assertTrue(exception.getContext().isEmpty());
    }

    @Test
    @DisplayName("Should be serializable")

        </field>
        <field>
          <name>version</name>
          <version>1.0.0+</version>
          <type>String</type>
          <description>The base version (i.e. ending in {@code -SNAPSHOT}) when this directory represents a "groupId/artifactId/version" for a SNAPSHOT.</description>
        </field>
        <field xdoc.separator="blank">
          <name>plugins</name>