# Classes as Dependencies

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

## A `dict` from the previous example

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

//// tab | Python 3.10+

```Python hl_lines="9"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="11"

   * That is, the first call to {@link #nextIndex()} will return {@code position}, and the first
   * call to {@link #next()} will return the element at that index, if available. Calls to {@link
   * #previous()} can retrieve the preceding {@code position} elements.
   *
   * @throws IndexOutOfBoundsException if {@code position} is negative or is greater than {@code
   *     size}

| xlVersionMinor | uint16         | Minor xl-meta version.
| xlMetaV2       | msgp bin array | Bin array with serialized metadata
| crc            | msgp uint      | Lower 32 bits of 64 bit xxhash of previous array contents (v1.2+ only)
| inline data    | binary         | Inline data if any, see Inline Data section for encoding.  
| [EOF] | |

## v1.0-v1.2 Versions

name: Crosscompile

on:
  pull_request:
    branches:
      - master

# This ensures that previous jobs for the PR are canceled when the PR is
# updated.
concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  build:
    name: Build Tests with Go ${{ matrix.go-version }} on ${{ matrix.os }}
    runs-on: ${{ matrix.os }}
    strategy:

	conf := Config{}

	if err := json.Unmarshal(stdin, &conf); err != nil {
		return nil, fmt.Errorf("failed to parse network configuration: %v", err)
	}

	log.Debugf("istio-cni: Config is: %+v", conf)
	// Parse previous result. Remove this if your plugin is not chained.
	if conf.RawPrevResult != nil {
		resultBytes, err := json.Marshal(conf.RawPrevResult)
		if err != nil {
			return nil, fmt.Errorf("could not serialize prevResult: %v", err)

name: Healing Functional Tests

on:
  pull_request:
    branches:
      - master

# This ensures that previous jobs for the PR are canceled when the PR is
# updated.
concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  build:
    name: Go ${{ matrix.go-version }} on ${{ matrix.os }}
    runs-on: ${{ matrix.os }}
    strategy:

// The zero value for Reader operates like a Reader of an empty slice.
type Reader struct {
	s        []byte
	i        int64 // current reading index
	prevRune int   // index of previous rune; or < 0
}

// Len returns the number of bytes of the unread portion of the
// slice.
func (r *Reader) Len() int {
	if r.i >= int64(len(r.s)) {
		return 0
	}
	return int(int64(len(r.s)) - r.i)
}

    id: error-handling-proposal
    attributes:
      label: Does this affect error handling?
      description: If so, how does this differ from previous error handling proposals?
      placeholder: |
       Yes or No

       If yes, 
        1.how does this differ from previous error handling proposals?

    validations:
      required: true

  - type: textarea
    id: generics-proposal
    attributes:

name: Upgrade old version tests

on:
  pull_request:
    branches:
      - master

# This ensures that previous jobs for the PR are canceled when the PR is
# updated.
concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  build:
    name: Go ${{ matrix.go-version }} on ${{ matrix.os }}
    runs-on: ${{ matrix.os }}
    strategy:

   * executor. The listener will have the corresponding transition method called whenever the
   * service changes state. The listener will not have previous state changes replayed, so it is
   * suggested that listeners are added before the service starts.
   *
   * <p>{@code addListener} guarantees execution ordering across calls to a given listener but not