code: func (b *OpenBitSet) Get(index int64) bool {
  	i := int(index >> 6) // div 64
  	if i >= len(b.bits) {
  		return false
  	}
  	bitmask := int64(1) << uint(index&0x3f)
  	return (b.bits[i] & bitmask) != 0
  }
docs: /* Returns true or false for the specified bit index */