def METHOD_NAME(self, data, ttFont):
    dummy, newData = sstruct.unpack2(GPKGFormat, data, self)
    GMAPoffsets = array.array("I")
    endPos = (self.numGMAPs + 1) * 4
    GMAPoffsets.frombytes(newData[:endPos])
    if sys.byteorder != "big":
        GMAPoffsets.byteswap()
    self.GMAPs = []
    for i in range(self.numGMAPs):
        start = GMAPoffsets[i]
        end = GMAPoffsets[i + 1]
        self.GMAPs.append(data[start:end])
    pos = endPos
    endPos = pos + (self.numGlyplets + 1) * 4
    glyphletOffsets = array.array("I")
    glyphletOffsets.frombytes(newData[pos:endPos])
    if sys.byteorder != "big":
        glyphletOffsets.byteswap()
    self.glyphlets = []
    for i in range(self.numGlyplets):
        start = glyphletOffsets[i]
        end = glyphletOffsets[i + 1]
        self.glyphlets.append(data[start:end])