code: def get_h2i(self, hdrs_usr):
          
          with open(self.fin) as fin_stream:
              for line in fin_stream:
                  line = line.rstrip('\r\n') # chomp
                  if not self.hdr2idx:
                      if self.do_hdr(line, hdrs_usr):
                          return self.hdr2idx
          return None
docs: Read csv/tsv file and return specified data in a list of lists.