def METHOD_NAME(self, tracks):
    """ write many tracks together
    """
    self.tracks.resize(self.tracks.shape[0] + tracks._data.shape[0],
                       axis=0)
    self.tracks[-tracks._data.shape[0]:] = tracks._data
    self.offsets.resize(self.offsets.shape[0] + tracks._offsets.shape[0],
                        axis=0)
    self.offsets[-tracks._offsets.shape[0]:] = \
        self.offsets[-tracks._offsets.shape[0] - 1] + \
        tracks._offsets + tracks._lengths