code: function isAtom(form, wrapped) {
    // it's an atom if we've tagged it one:
    var is = (typeof form === 'object' && form.__isatom);
    // but it's not if it's a list:
    is = is && !isList(form);
    // by default allow primitives as atoms
    if(!wrapped) {
      is = is || isPrimitive(form);
    }
  
    return is;
  }
docs: Returns if the specified value is an atom
  By default a primitive is considered an atom,
  pass true as the second arg to say it must
  be a *wrapped* primitive.