DataConversionWarning: A column-vector y was passed when a 1d array was expected. 问题解决?

数据转换警告：当需要一维数组时，传递了列向量y。请将Y的形状更改为（n_samples，），例如使用ravel（）。
  y = column_or_1d(y, warn=True)

model = forest.fit(train_fold, train_y)

model = forest.fit(train_fold, train_y.values.ravel())