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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, content, encoding='utf8'):
 """ add a line to file """

        if not self.parent.exists:
            self.parent.create()
        with open(self._filename, "ab") as output_file:
            if not is_text(content):
                Log.error(u"expecting to write unicode only")
            output_file.write(content.encode(encoding))
            output_file.write(b"\n")