docs: private ImmutableList<ExecutableElement> copyOfMethods(TypeMirror targetType) {
      if (!targetType.getKind().equals(TypeKind.DECLARED)) {
        return ImmutableList.of();
      }
      String copyOf = Optionalish.isOptional(targetType) ? "of" : "copyOf";
      TypeElement targetTypeElement = MoreElements.asType(typeUtils.asElement(targetType));
      ImmutableList.Builder<ExecutableElement> copyOfMethods = ImmutableList.builder();
      for (ExecutableElement method :
          ElementFilter.methodsIn(targetTypeElement.getEnclosedElements())) {
        if (method.getSimpleName().contentEquals(copyOf)
            && method.getParameters().size() == 1
            && method.getModifiers().contains(Modifier.STATIC)) {
          copyOfMethods.add(method);
        }
      }
      return copyOfMethods.build();
    }