code: def load_mldataset(filename):
      
      user = []
      item = []
      score = []
      with open(filename) as f:
          for line in f:
              tks = line.strip().split('\t')
              if len(tks) != 4:
                  continue
              user.append(int(tks[0]))
              item.append(int(tks[1]))
              score.append(float(tks[2]))
      user = mx.nd.array(user)
      item = mx.nd.array(item)
      score = mx.nd.array(score)
      return gluon.data.ArrayDataset(user, item, score)
docs: Not particularly fast code to parse the text file and load it into three NDArray's
      and product an NDArrayIter