Returns `<data_var>["<name>"] = <name>`.

def __get_subscript_assign(self, name):
    """
    Returns `<data_var>["<name>"] = <name>`.
    """

    return ast.Assign(
      targets=[self.__get_subscript(name, ast.Store())],
      value=ast.Name(id=name, ctx=ast.Load()))