file: line(s) /\z/
line: "G017RATEBRKRL" comma rate comma start_date comma end_date comma time newline { ... }
line: "G017CP111 D" comma start_rate comma end_rate comma change comma date comma time newline { ... }
line: "G017RPAGO/N" comma rate comma whitespace  comma whitespace  comma date comma time newline { ... }