'Copy any overrides the user has made on blocks in this library.'

def _copy_overrides(self, store, user_id, source, dest):

    for field in source.fields.itervalues():
        if ((field.scope == Scope.settings) and field.is_set_on(source)):
            setattr(dest, field.name, field.read_from(source))
    if source.has_children:
        source_children = [self.runtime.get_block(source_key) for source_key in source.children]
        dest_children = [self.runtime.get_block(dest_key) for dest_key in dest.children]
        for (source_child, dest_child) in zip(source_children, dest_children):
            self._copy_overrides(store, user_id, source_child, dest_child)
    store.update_item(dest, user_id)
