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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def filter_children(self, ctype: ContentType = None) -> List[SchemaNode]: """Return receiver's children based on content type. Args: ctype: Content type. """

        if ctype is None:
            ctype = self.content_type()
        return [c for c in self.children if
                not isinstance(c, (RpcActionNode, NotificationNode)) and
                c.content_type().value & ctype.value != 0]