'Appends a hook at the end of the list.
Args:
key: a unique key (within the module) for this particular function.
If something from the same module with the same key is already
registered, nothing will be added.
function: the hook to be added.
service: optional argument that restricts the hook to a particular api
Returns:
True if the collection was modified.'

def Append(self, key, function, service=None):

    return self.__Insert(len(self), key, function, service)
