public static Type toDoubleFunction(Type innerType) {
        return SimpleParameterizedType.create(ToDoubleFunction.class, innerType);
    }
Generates a {@link Type} to represent a java standard
{@link ToDoubleFunction} with generic type variables.

@param innerType  the inner type
@return           the resulting type

@since 2.5
common-parent/codegen/src/main/java/com/speedment/common/codegen/constant/DefaultType.java