doc1_07543210_sample_current.txt|CURRENT_SMOKER
doc1_07543210_sample_past_smoker.txt|PAST_SMOKER
doc1_07543210_sample_unknown.txt|UNKNOWN
doc2_07543210_sample_current.txt|CURRENT_SMOKER
doc2_07543210_sample_past_smoker.txt|PAST_SMOKER