title: using sklearn.train_test_split for Imbalanced data
body: <p>I have a very imbalanced dataset. I used sklearn.train_test_split function to extract the train dataset. Now I want to oversample the train dataset, so I used to count number of type1(my data set has 2 categories and types(type1 and tupe2)  but approximately all of my train data are type1. So I cant oversample.</p>
  
  <p>Previously I used to split train test datasets with my written code. In that code 0.8 of all type1 data and 0.8 of all type2 data were in the train dataset. </p>
  
  <p>How I can use this method with train_test_split function or other spliting methods in sklearn?</p>
  
  <p>*I should just use sklearn or my own written methods.</p>