You could also use it to generate code automatically, for clients that communicate with your API. For example, frontend, mobile or IoT applications.

## Recap, step by step

### Step 1: import `FastAPI`

{* ../../docs_src/first_steps/tutorial001.py hl[1] *}

`FastAPI` is a Python class that provides all the functionality for your API.

/// note | "Technical Details"

        include:
          - os: windows-latest
            java: 21
            root-pom: pom.xml
    runs-on: ${{ matrix.os }}
    env:
      ROOT_POM: ${{ matrix.root-pom }}
    steps:
      # Cancel any previous runs for the same branch that are still running.
      - name: 'Cancel previous runs'
        uses: styfle/cancel-workflow-action@85880fa0301c86cca9da44039ee3bb12d3bedbfa # 0.12.1
        with:

Sebastian Kozłowski <******@****.***> 1730047890 +0100

be used to select a different 'environment'.

## Installing

The new installer is intended to be modular and very explicit about what is installed. It has
far more steps than the Istio installer - but each step is smaller and focused on a specific
feature, and can be performed by different people/teams at different times.

It is strongly recommended that different namespaces are used, with different service accounts.

            CACHEBUSTER=${{ steps.tf-version.outputs.DATE }}
          tags: |
            tensorflow/build:latest-${{ matrix.python-version }}
            tensorflow/build:${{ steps.tf-version.outputs.TF_VERSION }}-${{ matrix.python-version }}
            gcr.io/tensorflow-sigs/build:latest-${{ matrix.python-version }}
            gcr.io/tensorflow-sigs/build:${{ steps.tf-version.outputs.TF_VERSION }}-${{ matrix.python-version }}

            PYTHON_VERSION=${{ matrix.python-version }}
            CACHEBUSTER=${{ steps.vars.outputs.DATE }}
          tags: |
            tensorflow/build:${{ steps.vars.outputs.REF }}-${{ matrix.python-version }}
            gcr.io/tensorflow-sigs/build:${{ steps.vars.outputs.REF }}-${{ matrix.python-version }}
          cache-from: type=registry,ref=tensorflow/build:${{ steps.vars.outputs.REF }}-${{ matrix.python-version }}
          cache-to: type=inline

        title: '${{ github.event.inputs.release_branch }} cherry-pick: ${{ steps.cherrypick.outputs.SHORTSHA }} "${{ steps.cherrypick.outputs.TITLE }}"'
        committer: TensorFlow Release Automation <******@****.***>
        token: ${{ secrets.JENKINS_TOKEN }}
        base: ${{ github.event.inputs.release_branch }}
        branch: ${{ github.event.inputs.release_branch }}-${{ steps.cherrypick.outputs.SHORTSHA }}
        reviewers: learning-to-play

* Share database connections.
* Enforce security, authentication, role requirements, etc.
* And many other things...

All these, while minimizing code repetition.

## First Steps

Let's see a very simple example. It will be so simple that it is not very useful, for now.

But this way we can focus on how the **Dependency Injection** system works.

### Create a dependency, or "dependable"

name: PyLint
on:
  pull_request:
    paths:
      - '**.py'

permissions:
  contents: read

jobs:
  build:
    name: PyLint
    runs-on: ubuntu-latest
    steps:
    - name: Checkout code
      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
    - name: Get file changes
      id: get_file_changes

{* ../../docs_src/security/tutorial005_an_py310.py hl[5,9,13,47,65,106,108:116,122:125,129:135,140,156] *}

Now let's review those changes step by step.

## OAuth2 Security scheme

The first change is that now we are declaring the OAuth2 security scheme with two available scopes, `me` and `items`.