code: def create(cls, root, schema):
          
          fn = cls.tags.get(root.name)
          if fn is not None:
              return fn(schema, root)
          else:
              return None
docs: Create an object based on the root tag name.
          @param root: An XML root element.
          @type root: L{Element}
          @param schema: A schema object.
          @type schema: L{schema.Schema}
          @return: The created object.
          @rtype: L{SchemaObject}