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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 normalize_linefeeds(self, a_string):
 """Convert `\r\r\n`,`\r\n`, `\n\r` to `\n.` :param a_string: A string that may have non-normalized line feeds i.e. output returned from device, or a device prompt :type a_string: str """

        newline = re.compile("(\r\r\r\n|\r\r\n|\r\n|\n\r)")
        a_string = newline.sub(self.RESPONSE_RETURN, a_string)
        if self.RESPONSE_RETURN == "\n":
            # Convert any remaining \r to \n
            return re.sub("\r", self.RESPONSE_RETURN, a_string)