code: func AddPkcs7(data []byte, blockSize int) []byte {
  	
  	var paddingCount int
  	
  	if paddingCount = blockSize - (len(data) % blockSize);paddingCount == 0 {
  		paddingCount=blockSize
  	}		
  	
  	return append(data, bytes.Repeat([]byte{byte(paddingCount)}, paddingCount)...)
  }
docs: // AddPkcs7 pads given byte array using pkcs7 padding schema till it has blockSize length in bytes