'Handles loading container namespaces when necessary.
See ``Repo`` for how actual package modules are loaded.'

def load_module(self, fullname):

    if (fullname in sys.modules):
        return sys.modules[fullname]
    if (not self.by_namespace.is_prefix(fullname)):
        raise ImportError(('No    such    Spack    repo:    %s' % fullname))
    module = SpackNamespace(fullname)
    module.__loader__ = self
    sys.modules[fullname] = module
    return module
