function compose(...args) {
    const descriptor = [this, ...args].reduce(mergeComposable, {});
    return createStamp(descriptor);
  }
Given the list of composables (stamp descriptors and stamps) returns
a new stamp (composable factory function).
@typedef {Function} Compose
Parameters:  {...Composable} The list of composables.
@returns {Stamp} A new stamp (aka composable factory function)