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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 init_default(self):
 """Overriden to take default database and save locally The issue was that init_default() sets self.filename to None; however there can be no SQLite database without a corresponding file (not using *memory* here) Should not keep default file open either (as it is in the API directory and shouldn't be messed by user) """

        import f311
        if self.default_filename is None:
            raise RuntimeError("Class '{}' has no default filename".format(self.__class__.__name__))
        fullpath = f311.get_default_data_path(self.default_filename, class_=self.__class__)
        self.load(fullpath)
        name, ext = os.path.splitext(self.default_filename)
        new = a99.new_filename(os.path.join("./", name), ext)
        self.save_as(new)