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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 _visit_body(self, node):
 """ Traverse the body of the node manually. If the first node is an expression which contains a string or bytes it marks that as a docstring. """

        if (node.body and isinstance(node.body[0], ast.Expr) and
                self.is_base_string(node.body[0].value)):
            node.body[0].value.is_docstring = True
            self.visit(node.body[0].value)

        for sub_node in node.body:
            self.visit(sub_node)