Help defining NimbleCSV

What have you tried so far? It works for me:

NimbleCSV.define(MyParser, separator: "\t", newlines: ["\r", "\r\n", "\n"])

Then in iex:

MyParser.parse_string("agency_id\tagency_name\tagency_url\tagency_timezone\tagency_lang\rBART\tBay Area Rapid Transit\thttp://www.bart.gov\tAmerica/Los_Angeles\ten")
[
  ["BART", "Bay Area Rapid Transit", "http://www.bart.gov",
   "America/Los_Angeles", "en"]
]