code: func (sba *sparseBitArray) Nand(other BitArray) BitArray {
  	if ba, ok := other.(*sparseBitArray); ok {
  		return nandSparseWithSparseBitArray(sba, ba)
  	}
  
  	return nandSparseWithDenseBitArray(sba, other.(*bitArray))
  }
docs: // Nand will return the result of doing a bitwise and not of the bit array
  // with the other bit array on each block.