code: def merge(l1, l2):
      
      x1, y1, x2, y2 = l1
      xx1, yy1, xx2, yy2 = l2
  
      comb = ((x1, y1, xx1, yy1),
              (x1, y1, xx2, yy2),
              (x2, y2, xx1, yy1),
              (x2, y2, xx2, yy2))
  
      d = [length(c) for c in comb]
      i = argmax(d)
  
      dist = d[i]
      mid = middle(comb[i])
  
      a = (angle(l1) + angle(l2)) * 0.5
      return fromAttr(mid, a, dist)
docs: merge 2 lines together