code: def intervals(_min, _max=None, size=1):
      
      if _max == None:
          _max = _min
          _min = 0
      _max = int(mo_math.ceiling(_max))
      _min = int(mo_math.floor(_min))
  
      output = ((x, min(x + size, _max)) for x in _range(_min, _max, size))
      return output
docs: RETURN (min, max) PAIRS OF GIVEN SIZE, WHICH COVER THE _min, _max RANGE
      THE LAST PAIR MAY BE SMALLER
      Yes!  It's just like range(), only cooler!