manipulating an existing plot !

[ram rokr]

Hello,
     I already have a script that plots a polygon. But now I'm trying to script a python class that would enable me to import the previous plot , make instances and control it too(like specifying parameters like spacing , width, height or the like). My approach was, to create a new layout and try to import the exisiting plot and then try to make instances and manipulate it. 

class DerivedClass(BaseClass):
 
  def __init__(self, layout,topcell):
      self.layout = pya.Layout()
      self.layout.dbu = 0.001
      self.topcell = self.layout.create_cell("TOP")
      l1 = layout.layer(1, 0)
      topcell.shapes(l1).insert(pya.Box(0, 0, 1000, 2000))
      
      self.path = []
  def add_new(self,path):
      self.path.append(path)

      
     
How could I use layer mapping or any other method to accomplish this? Looking forward to your advise. Thanks.