```

Note that, you can add as many MySQL server endpoint configurations as needed by providing an identifier (like "myinstance" in the example above) for each MySQL instance desired.

Restart the MinIO server to put the changes into effect. The server will print a line like `SQS ARNs: arn:minio:sqs::myinstance:mysql` at start-up, if there are no errors.

        assertTrue(SessionSetupHandler.class.isAssignableFrom(impl.getClass()), "Type should be assignable");
    }

    @Test
    @DisplayName("Edge: null is not an instance of the interface")
    void testNullIsNotInstance() {
        // Assert
        assertFalse(SessionSetupHandler.class.isInstance(null));
    }

    @Test

      @ParametricNullness T instance) {
    return new SupplierOfInstance<>(instance);
  }

  private static final class SupplierOfInstance<T extends @Nullable Object>
      implements Supplier<T>, Serializable {
    @ParametricNullness final T instance;

    SupplierOfInstance(@ParametricNullness T instance) {
      this.instance = instance;
    }

    @Override
    @ParametricNullness
    public T get() {

      @ParametricNullness T instance) {
    return new SupplierOfInstance<>(instance);
  }

  private static final class SupplierOfInstance<T extends @Nullable Object>
      implements Supplier<T>, Serializable {
    @ParametricNullness final T instance;

    SupplierOfInstance(@ParametricNullness T instance) {
      this.instance = instance;
    }

    @Override
    @ParametricNullness
    public T get() {

        // Arrange: create an implementation instance
        SmbRenewableCredentials impl = supplier.get();

        // Act: call renew
        CredentialsInternal renewed = impl.renew();

        // Assert: verify behavior based on scenario
        if (expectSame) {
            assertSame(impl, renewed, "renew() should return the same instance");
        } else if (expectNew) {

        // Act & Assert
        // unwrap to interface itself should return same instance
        CredentialsInternal unwrapped = creds.unwrap(CredentialsInternal.class);
        assertNotNull(unwrapped, "unwrap to CredentialsInternal returns instance");
        assertSame(creds, unwrapped, "unwrap returns the same object instance");

        // unwrap to unrelated type should return null (use another Credentials implementation)

    void testGetInstanceWithoutSetInstance() {
        // Test getInstance when no instance has been set
        // Should default to System.err
        LogStream instance = LogStream.getInstance();
        assertNotNull(instance);

        // Getting instance again should return the same instance
        LogStream instance2 = LogStream.getInstance();
        assertSame(instance, instance2);
    }

    @Test

        byte[] buffer = new byte[] { (byte) 0xff, (byte) 0xff, 0, 0, 0, 0, 0, 0 };
        SmbComWriteAndXResponse instance = new SmbComWriteAndXResponse(config);

        // When
        int result = instance.readParameterWordsWireFormat(buffer, 0);

        // Then
        assertEquals(8, result);
        assertEquals(0xffffL, instance.getCount());
    }

    /**
     * Test of readParameterWordsWireFormat with zero count
     */

      this.wrapped = checkNotNull(wrapped);
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      // In general getClass().isInstance() is bad for equals.
      // But here we fully control the subclasses to ensure symmetry.
      if (getClass().isInstance(obj)) {
        Wrapper that = (Wrapper) obj;
        return wrapped.equals(that.wrapped);
      }
      return false;
    }

    @Override

But we want to be able to parameterize that fixed content.

## A "callable" instance { #a-callable-instance }

In Python there's a way to make an instance of a class a "callable".

Not the class itself (which is already a callable), but an instance of that class.

To do that, we declare a method `__call__`:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[12] *}