'Ensure that all schemas within the collection
import each other which has a blending effect.
@return: self
@rtype: L{SchemaCollection}'

def autoblend(self):

    namespaces = self.namespaces.keys()
    for s in self.children:
        for ns in namespaces:
            tns = s.root.get('targetNamespace')
            if (tns == ns):
                continue
            for imp in s.root.getChildren('import'):
                if (imp.get('namespace') == ns):
                    continue
            imp = Element('import', ns=Namespace.xsdns)
            imp.set('namespace', ns)
            s.root.append(imp)
    return self
