code: def generateRandomSymbol(numColumns, sparseCols):
    
    symbol = list()
    remainingCols = sparseCols
    while remainingCols > 0:
      col = random.randrange(numColumns)
      if col not in symbol:
        symbol.append(col)
        remainingCols -= 1
    return symbol
docs: Generates a random SDR with sparseCols number of active columns
    
    @param numColumns (int) number of columns in the temporal memory
    @param sparseCols (int) number of sparse columns for desired SDR  
    @return symbol (list) SDR