Call a function in an observer from another observer

Question

I'm trying to call a function in an observer from another observer. I have a custom product type I've created called assembly. In my assembly config.xml

    <catalog_product_prepare_save>
        <observers>
            <assembly_observer>
                <class>assembly/observer</class>
                <method>prepareProductSave</method>
            </assembly_observer>
        </observers>
    </catalog_product_prepare_save>

and in the model/observer.php

class MyNamespace_Assembly_Model_Observer
{
    public function MyFunction($observer)
    {
    }
}

How do I call MyFunction($observer) from an observer I have in another module?

Answer 1

Like any other model function:

Mage::getSingleton('assembly/observer')->MyFunction(...);

or, if you do not work with singleton observers:

Mage::getModel('assembly/observer')->MyFunction(...);