Why a SeqRecord?

def parse(input, handler):
  for line in input:
    handler.process_line(line[:2], line)
  return handler.get_record()

parse(open(filename), BuildSeqRecord())

class BuildSeqRecord:
  def __init__(self):
    self.accessions = []

  def process_line(self, tag, line):
    if tag == "AC":
      words = line.replace(";", " ").split()
      self.accessions.extend(words[1:])
      return

  def get_record(self):
    return SeqRecord(...
                     accessions = accession,
                     ...)