code: def _frange(start, stop=None, step=None):
      
      if stop is None:
          stop = start
          start = 0.0
      if step is None:
          step = 1.0
      r = start
      while r < stop:
          yield r
          r += step
docs: _frange range like function for float inputs
      :param start:
      :type start:
      :param stop:
      :type stop:
      :param step:
      :type step:
      :return:
      :rtype: