docs: def parse_numtuple(s,intype,length=2,scale=1):
      '''parse a string into a list of numbers of a type'''
      if intype == int:
          numrx = intrx_s;
      elif intype == float:
          numrx = fltrx_s;
      else:
          raise NotImplementedError("Not implemented for type: {}".format(
              intype));
      if parse_utuple(s, numrx, length=length) is None:
          raise ValueError("{} is not a valid number tuple.".format(s));
      return [x*scale for x in evalt(s)];