def METHOD_NAME( f, len ):
    global Setsdrmasks, SetsdrmasksOnesCount
    byteCount = (len+7)//8
    Setsdrmasks = f.read( byteCount )
    ls = []
    SetsdrmasksOnesCount = 0
    for b in Setsdrmasks:
        ls.append( "%x" % ((b & 0xf0) >> 4) )
        ls.append( "%x" % ( b & 0x0f ) )
        for i in range(8):
            if b & (1<<i):
                SetsdrmasksOnesCount = SetsdrmasksOnesCount +1
    return ''.join(ls)