docs: def _MakeRanges(pairs):
    """Turn a list like [(65,97), (66, 98), ..., (90,122)]
       into [(65, 90, +32)]."""
    ranges = []
    last = -100
  
    def evenodd(last, a, b, r):
      if a != last+1 or b != _AddDelta(a, r[2]):
        return False
      r[1] = a
      return True
  
    def evenoddpair(last, a, b, r):
      if a != last+2:
        return False
      delta = r[2]
      d = delta
      if type(delta) is not str:
        return False
      if delta.endswith('Skip'):
        d = delta[:-4]
      else:
        delta = d + 'Skip'
      if b != _AddDelta(a, d):
        return False
      r[1] = a
      r[2] = delta
      return True
  
    for a, b in pairs:
      if ranges and evenodd(last, a, b, ranges[-1]):
        pass
      elif ranges and evenoddpair(last, a, b, ranges[-1]):
        pass
      else:
        ranges.append([a, a, _Delta(a, b)])
      last = a
    return ranges