///

### Step 2: create a `FastAPI` "instance" { #step-2-create-a-fastapi-instance }

{* ../../docs_src/first_steps/tutorial001_py39.py hl[3] *}

Here the `app` variable will be an "instance" of the class `FastAPI`.

This will be the main point of interaction to create all your API.

                "To install, run: pip install email-validator"
            )
            return str(v)

        @classmethod
        def _validate(cls, __input_value: Any, _: Any) -> str:
            logger.warning(
                "email-validator not installed, email fields will be treated as str.\n"
                "To install, run: pip install email-validator"
            )

     * @param deploymentRepository the repository to deploy to
     * @param localRepository the local repository to install into
     * @throws ArtifactDeploymentException if an error occurred deploying the artifact
     * @deprecated to be removed before 2.0 after the install/deploy plugins use the alternate
     *             method
     */
    @Deprecated
    void deploy(
            String basedir,

def test_fastapi_cli_not_installed():
    with patch.object(fastapi.cli, "cli_main", None):
        with pytest.raises(RuntimeError) as exc_info:
            fastapi.cli.main()

package cmd

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[rebalanceMetricRebalanceBuckets-0]
	_ = x[rebalanceMetricRebalanceBucket-1]
	_ = x[rebalanceMetricRebalanceObject-2]

### Install requirements

After activating the environment, install the required packages:

//// tab | `pip`

<div class="termy">

```console
$ pip install -r requirements.txt

---> 100%
```

</div>

////

//// tab | `uv`

/// info

To receive uploaded files, first install <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

```console
$ pip install python-multipart
```

This is because uploaded files are sent as "form data".

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>test</groupId>
    <artifactId>test</artifactId>
    <version>0.1-SNAPSHOT</version>

    <dependencyManagement>
        <dependencies>

// Code generated by "stringer -type=format -trimprefix=format untar.go"; DO NOT EDIT.

package cmd

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[formatUnknown-0]
	_ = x[formatGzip-1]
	_ = x[formatZstd-2]
	_ = x[formatLZ4-3]
	_ = x[formatS2-4]
	_ = x[formatBZ2-5]
}

 */
@Deprecated(since = "4.0.0")
public final class Maven3ScopeManagerConfiguration implements ScopeManagerConfiguration {
    public static final Maven3ScopeManagerConfiguration INSTANCE = new Maven3ScopeManagerConfiguration();
    public static final String DS_COMPILE = "compile";
    public static final String DS_RUNTIME = "runtime";
    public static final String DS_PROVIDED = "provided";