Valid Currency

Is this valid currency? Will I be able to cash this in for face value?

I was making meatloaf when I noticed Mary writing diligently, then gathering her brother and sister for a whispered consultation. After they agreed that she could sign their names to a proclamation, she delivered this to me along with her beaming smiles:

"Deer Katherine

We promis that we will be obedient and good for you and will also be nice.

Sinde John Mary Margaret"

I feel like I won the Mommy Lottery!

(No, my five-year-old doesn't call me by my given name. But she recently learned how to spell it, so is this week enthralled with writing me notes to my name instead of my title.)