How to use the klayout.db.Layout function in klayout

def test_3(self):
    # db plugins loaded?
    v = db.Layout()
    v.read(os.path.join(os.path.dirname(__file__), "..", "gds", "t10.gds"))
    self.assertEqual(v.top_cell().name, "RINGO")

#the Free Software Foundation, either version 2 of the License, or
#(at your option) any later version.
#
#Pill is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU General Public License for more details.
#
#You should have received a copy of the GNU General Public License
#along with Pill.  If not, see .


import klayout.db as db
import klayout.lib

layout = db.Layout()
layout.dbu = .001
top = layout.create_cell("nch")

f = open("tsmcN65.layermap").read().split("\n")
layermap = {}
for l in f:
  if len(l) < 1:
     continue
  if l[0] == "#":
     continue
  l = l.split()
  if len(l) != 4:
      continue
  layermap[ (l[0],l[1]) ] = [int(l[2]),int(l[3])]
  
#print layermap

import inspect
import sys
import os
import re
import props
from tools import Lazy

import klayout.db as db
import klayout.lib
import tools
import math
import context
import geom
import uuid

layout = db.Layout()
layout.dbu = .001

######## These are implementations of Skill standard library functions
def getsqg(*s):
   print("*****GetSqG" + str(len(s)))
   ret = None
   #print s[0]
   print(s[1])
   l = s[0]

   if not l:
      return l

   if isinstance(l,props.PropertyDict):
      print("was property dict")
      if s[1] in l: