* So, by using FastAPI you are saving development time, bugs, lines of code, and you would probably get the same performance (or better) you would if you didn't use it (as you would have to implement it all in your code).

If the passwords don't match, we return the same error.

#### Password hashing { #password-hashing }

"Hashing" means: converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

You could also use `from starlette.requests import Request` and `from starlette.responses import JSONResponse`.

**FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette. The same with `Request`.

///

## Override the default exception handlers { #override-the-default-exception-handlers }

 *
 * <p><b>Warning:</b> instances of type {@code Multimap} may not implement {@link Object#equals} in
 * the way you expect. Multimaps containing the same key-value pairs, even in the same order, may or
 * may not be equal and may or may not have the same {@code hashCode}. The recommended subinterfaces
 * provide much stronger guarantees.
 *
 * <h3>Comparison to a map of collections</h3>
 *

                }
            }
        }
    }
}
```

## Additional media types for the main response { #additional-media-types-for-the-main-response }

You can use this same `responses` parameter to add different media types for the same main response.

For example, you can add an additional media type of `image/png`, declaring that your *path operation* can return a JSON object (with media type `application/json`) or a PNG image:

   * even in the same order. (It is guaranteed to return true for instances constructed from the
   * same values in the same order if {@code strictfp} is in effect, or if the system architecture
   * guarantees {@code strictfp}-like semantics.)
   */
  @Override
  public boolean equals(@Nullable Object obj) {
    if (obj == null) {
      return false;
    }
    if (getClass() != obj.getClass()) {
      return false;
    }

You can define Header parameters the same way you define `Query`, `Path` and `Cookie` parameters.

## Import `Header` { #import-header }

First import `Header`:

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[3] *}

## Declare `Header` parameters { #declare-header-parameters }

Then declare the header parameters using the same structure as with `Path`, `Query` and `Cookie`.

        // Second call should return cached value (same as first)
        Subject second = auth.getSubject();
        if (first == null && second == null) {
            // Both null - caching is working
            assertNull(second, "Second getSubject should return same result as first (both null)");
        } else if (first != null && second != null) {
            // Both non-null - should be same instance

    }
  }

  /**
   * Returns a hash code, having the same bit length as each of the input hash codes, that combines
   * the information of these hash codes in an ordered fashion. That is, whenever two equal hash
   * codes are produced by two calls to this method, it is <i>as likely as possible</i> that each
   * was computed from the <i>same</i> input hash codes in the <i>same</i> order.
   *

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

### Why use password hashing { #why-use-password-hashing }