in read_csv, warn_bad_lines and error_bad_lines have misleading names
read_csv will still fail if *_bad_lines=False. *_bad_lines only applies when the number of delimiters is wrong. This is misleading, a line with a poorly formatted date is what I would think of as a "bad_line" that should be ignored  (cf https://stackoverflow.com/questions/22026181 )
