*
   * @param formal The type whose type variables or itself is mapped to other type(s). It's almost
   *     always a bug if {@code formal} isn't a type variable and contains no type variable. Make
   *     sure you are passing the two parameters in the right order.
   * @param actual The type that the formal type variable(s) are mapped to. It can be or contain yet

   *
   * @param formal The type whose type variables or itself is mapped to other type(s). It's almost
   *     always a bug if {@code formal} isn't a type variable and contains no type variable. Make
   *     sure you are passing the two parameters in the right order.
   * @param actual The type that the formal type variable(s) are mapped to. It can be or contain yet

    private final String name;
    private final ImmutableList<Type> bounds;

    TypeVariableImpl(D genericDeclaration, String name, Type[] bounds) {
      disallowPrimitiveType(bounds, "bound for type variable");
      this.genericDeclaration = checkNotNull(genericDeclaration);
      this.name = checkNotNull(name);
      this.bounds = ImmutableList.copyOf(bounds);
    }

    @Keep
    public Type[] getBounds() {

    private final String name;
    private final ImmutableList<Type> bounds;

    TypeVariableImpl(D genericDeclaration, String name, Type[] bounds) {
      disallowPrimitiveType(bounds, "bound for type variable");
      this.genericDeclaration = checkNotNull(genericDeclaration);
      this.name = checkNotNull(name);
      this.bounds = ImmutableList.copyOf(bounds);
    }

    @Keep
    public Type[] getBounds() {

    }

    TypeToken<V> valueType() {
      return new TypeToken<V>(getClass()) {};
    }
  }

  // The A and B type parameters are used inside the test to test type variable
  public <A, B> void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            TypeToken.of(String.class),
            TypeToken.of(String.class),

    }

    TypeToken<V> valueType() {
      return new TypeToken<V>(getClass()) {};
    }
  }

  // The A and B type parameters are used inside the test to test type variable
  public <A, B> void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            TypeToken.of(String.class),
            TypeToken.of(String.class),

This means that now, if you set a value in a context variable before `yield`, the value would still be available after `yield` (as you would intuitively expect). And it also means that you can reset the context variable with a token afterwards.

For example, this works correctly now:

```Python
from contextvars import ContextVar