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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 pack(self):
 """ Create a string representation from object state. @return: The string (bytes) for this stomp frame. @rtype: C{str} """


        self.headers.setdefault('content-length', len(self.body))

        # Convert and append any existing headers to a string as the
        # protocol describes.
        headerparts = ("{0}:{1}\n".format(key, value)
                       for key, value in self.headers.items())

        # Frame is Command + Header + EOF marker.
        return six.b("{0}\n{1}\n".format(self.cmd, "".join(headerparts))) + (self.body if isinstance(self.body, six.binary_type) else six.b(self.body)) + six.b('\x00')