def __setitem__(self, name, vessel):
try:
attrs = vessel.nodespaces["__attrs__"]
except KeyError:
raise ValueError(u"Attributes need to be set.")
nextvessel = AttributedNode()
nextvessel.__name__ = name
nextvessel.attribute_access_for_attrs = False
principal = self.principal_factory(nextvessel, attraliaser=self.principal_attraliaser)
principal.__name__ = name
principal.__parent__ = self
# XXX: we could cache here, given that we are based on a LazyNode or
# similar
for key, val in attrs.iteritems():
principal.attrs[key] = val
self.context[name] = nextvessel
