Anomaly if baseline vs result counts differ, an empty list otherwise.

def GotAll(self, baseline, results):
    """Anomaly if baseline vs result counts differ, an empty list otherwise."""
    num_base = len(baseline)
    num_rslt = len(results)
    if num_rslt > num_base:
      raise ProcessingError("Filter generated more results than base data: "
                            "%s > %s" % (num_rslt, num_base))
    if num_rslt == num_base and num_base > 0:
      return self.Issue("Found all", results)
    return []