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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 append(self, filename, content, binary=False):
 """Appends given content to given filename."""


        self._raise_if_none()
        fn = path_join(self.path, filename)

        if binary:
            flags = 'ab'
        else:
            flags = 'a'

        with open(fn, 'a') as f:
            f.write(content)
            return True