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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 _handle_child( self, node: SchemaNode, stmt: Statement, sctx: SchemaContext) -> None: """Add child node to the receiver and handle substatements."""

        if not sctx.schema_data.if_features(stmt, sctx.text_mid):
            return
        node.name = stmt.argument
        node.ns = sctx.default_ns
        node._get_description(stmt)
        self._add_child(node)
        node._handle_substatements(stmt, sctx)