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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 marshall_key(self, key):
 """ Marshalls a Crash key to be used in the database. @see: L{__init__} @type key: L{Crash} key. @param key: Key to convert. @rtype: str or buffer @return: Converted key. """

        if key in self.__keys:
            return self.__keys[key]
        skey = pickle.dumps(key, protocol = 0)
        if self.compressKeys:
            skey = zlib.compress(skey, zlib.Z_BEST_COMPRESSION)
        if self.escapeKeys:
            skey = skey.encode('hex')
        if self.binaryKeys:
            skey = buffer(skey)
        self.__keys[key] = skey
        return skey