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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 readline(self):
 """ Read and return a line of text. :rtype: str :return: the next line of text in the file, including the newline character """

        _complain_ifclosed(self.closed)
        line = self.f.readline()
        if self.__encoding:
            return line.decode(self.__encoding, self.__errors)
        else:
            return line