Kaggle competition: Airbus Ship Detection Challenge
<prepare_x_and_y><EOS> 
test_files = [f for f in os.listdir(".. /input/test/")]
df = pd.read_csv(".. /input/test_ship_segmentations.csv")
 df = df[df['ImageId'].isin(test_files)].drop_duplicates(subset="ImageId")
 df.to_csv("submission.csv", index=False)
 len(df )