* Returns a message code.
     *
     * @return message code
     */
    public String getMessageCode() {
        return messageCode;
    }

    /**
     * Returns arguments of a message
     *
     * @return array of arguments
     */
    public Object[] getArgs() {
        return args;
    }

    @Override
    public String getMessage() {
        return message;
    }

    /**

            is ClassifierDescriptorWithTypeParameters -> declaration.declaredTypeParameters.isNotEmpty() && arguments.isEmpty()
            else -> false
        }
    }

    override fun TypeConstructorMarker.typeWithArguments(arguments: List<KotlinTypeMarker>): SimpleTypeMarker {
        if (this is ErrorTypeConstructor) {
            return ErrorUtils.createErrorType(kind, this, *formatParams)

   *     argument. These are matched by position - the first {@code %s} gets {@code
   *     errorMessageArgs[0]}, etc. Unmatched arguments will be appended to the formatted message in
   *     square braces. Unmatched placeholders will be left as-is.
   * @param errorMessageArgs the arguments to be substituted into the message template. Arguments

            }

            is FirVarargArgumentsExpression -> {
                // Vararg arguments may have multiple independent expressions associated.
                // Choose one to be the representative PSI value for the entire assembled argument.
                val (annotationValues, representativePsi) = arguments.convertVarargsExpression(builder)

    return KtAnnotationApplicationWithArgumentsInfo(
        classId = toAnnotationClassId(builder.rootSession),
        psi = psi as? KtCallElement,
        useSiteTarget = useSiteTarget,
        arguments = arguments,
        index = index,
        constructorSymbolPointer = with(builder.analysisSession) { constructorSymbol?.createPointer() },
        token = builder.token,
    )
}

from unicorn import UnicornMiddleware

app = FastAPI()

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

`app.add_middleware()` receives a middleware class as the first argument and any additional arguments to be passed to the middleware.

## Integrated middlewares

**FastAPI** includes several middlewares for common use cases, we'll see next how to use them.

!!! note "Technical Details"

                else -> fe10Type.getValueParameterTypesFromFunctionType()
            }.map { it.type.toKtType(analysisContext) }
        }

    override val returnType: KtType
        get() = withValidityAssertion {
            when {
                descriptor.functionTypeKind.isReflectType -> fe10Type.arguments.last().type

    boolean guarded = isGuarded(method);
    boolean timed = isTimed(method);
    Object[] arguments = new Object[(guarded ? 1 : 0) + (timed ? 2 : 0)];
    if (guarded) {
      arguments[0] = guard;
    }
    if (timed) {
      arguments[arguments.length - 2] = timeout.millis;
      arguments[arguments.length - 1] = TimeUnit.MILLISECONDS;
    }
    try {
      Object result;
      doingCallLatch.countDown();

        val result = LinkedHashMap<KtExpression, KtVariableLikeSignature<KtValueParameterSymbol>>()
        for ((parameter, arguments) in valueArguments) {
            val parameterSymbol = KtFe10DescValueParameterSymbol(parameter, analysisContext)

            for (argument in arguments.arguments) {
                val expression = argument.getArgumentExpression() ?: continue

   *     argument. These are matched by position - the first {@code %s} gets {@code
   *     errorMessageArgs[0]}, etc. Unmatched arguments will be appended to the formatted message in
   *     square braces. Unmatched placeholders will be left as-is.
   * @param errorMessageArgs the arguments to be substituted into the message template. Arguments