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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 masked_middle_mfcc(self):
 """ Return the MFCC speech frames in the MIDDLE portion of the wave. :rtype: :class:`numpy.ndarray` (2D) """

        begin, end = self._masked_middle_begin_end()
        return (self.masked_mfcc)[:, begin:end]