No, you only implement this one:

  def parseLog(file):
    list = []
    for line in file:
      list.append(parseEntry(line))
    return list

Or better (more pythonic imho):

  def parseLog(file):
    for line in file:
      yield parseEntry(line)

The second version is lazy (if file reading is lazy), so you can even abort parsing or fix the state on an error. Here are your different versions all reusing parseLog from above and equivalent line count to condition handling:

  def parseLogLoudly(file):
    for entry in parseLog(file):
      if entry.failed:
        print "Warning:", entry.message
      else
        yield entry

  def parseLogSilently(file):
    for entry in parseLog(file):
      if not entry.failed:
        yield entry

  def parseLogInteractively(file):
    for entry in parseLog(file):
      if entry.failed:
        yield askToFixEntry(entry)
      else
        yield entry

(Haskell's Either has "Left a" or "Right b". I want something like "Just value" or "Error msg", but you are right Either is nearer than Maybe)