### Bigger Errors - Crashes { #bigger-errors-crashes }

Nevertheless, there might be cases where we write some code that **crashes the entire application** making Uvicorn and Python crash. 💥

*   Fixes multiple crashes due to overflow and `CHECK`-fail in ops with large
    tensor shapes
    ([CVE-2021-41197](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41197))
*   Fixes a crash in `max_pool3d` when size argument is 0 or negative
    ([CVE-2021-41196](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41196))
*   Fixes a crash in `tf.math.segment_*` operations

# 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] *}

    }

    /**
     * Test the getErrorString method with various error classes and codes to ensure all branches are covered.
     */
    @ParameterizedTest
    @MethodSource("provideErrorClassAndCodeForGetErrorString")
    @DisplayName("getErrorString should return correct messages for all defined error classes and codes")
    void testGetErrorString(int errorClass, int errorCode, String expectedMessage) {

        if: failure() || cancelled()
        with:
          name: ${{ github.run_number }}-integration-test-artifact-${{ runner.os }}-${{ matrix.java }}

But remember that when you import `Query`, `Path`, `Header`, and others from `fastapi`, those are actually functions that return special classes.

///

/// info

To declare headers, you need to use `Header`, because otherwise the parameters would be interpreted as query parameters.

///

## Automatic conversion { #automatic-conversion }

A middleware doesn't have to be made for FastAPI or Starlette to work, as long as it follows the ASGI spec.

In general, ASGI middlewares are classes that expect to receive an ASGI app as the first argument.

So, in the documentation for third-party ASGI middlewares they will probably tell you to do something like:

```Python
from unicorn import UnicornMiddleware

* `Optional`
* ...and others.

////

//// tab | Python 3.8+

* `List`
* `Tuple`
* `Set`
* `Dict`
* `Union`
* `Optional`
* ...and others.

////

### Classes as types { #classes-as-types }

You can also declare a class as the type of a variable.

Let's say you have a class `Person`, with a name:

{* ../../docs_src/python_types/tutorial010.py hl[1:3] *}

        }

        @Test
        @DisplayName("Should support different file system information classes")
        void shouldSupportDifferentFileSystemInformationClasses() {
            // Test all known constants
            byte[] classes = { FileSystemInformation.SMB_INFO_ALLOCATION, FileSystemInformation.FS_SIZE_INFO,

        }
    }

    /**
     * Traverses classes contained in a Jar file.
     * <p>
     * If the specified Jar file has the extension <code>.war</code>, only entries whose path starts with the prefix <code>WEB-INF/classes</code> are traversed.
     * The handler receives the entry name excluding the prefix. For example, if the Jar file contains <code>/WEB-INF/classes/ccc/ddd/Eee.class</code>,