Abaqus Python Scripting..Key error

[maddy]

from abaqus import *
from abaqusConstants import *
from caeModules import *
from driverUtils import executeOnCaeStartup
import odbAccess
from odbAccess import openOdb
from part import *
from material import *
from section import *
from assembly import *
from step import *
from interaction import *
from load import *
from mesh import *
from optimization import *
from job import *
from sketch import *
from visualization import *
from connectorBehavior import *
o1 = session.openOdb(name='C:/Temp/Job-12.odb')
El_list=[13, 40, 30, 12]
session.viewports['Viewport: 1'].odbDisplay.display.setValues(plotState=(
CONTOURS_ON_DEF, ))
for el_num in El_list:
session.xyDataListFromField(odb=o1, outputPosition=INTEGRATION_POINT, variable=(('PEEQ', INTEGRATION_POINT), ('S', INTEGRATION_POINT, ((
INVARIANT, 'Mises'), )), ), elementLabels=(('PART-1-1', (
str(el_num), )), ), )
xy1 = session.xyDataObjects['PEEQ PI: PART-1-1 E: '+str(el_num)+' IP: 1']
xy2 = session.xyDataObjects['S:Mises PI: PART-1-1 E: '+str(el_num)+' IP: 1']
xy3 = combine(xy1, xy2)
xy3.setValues(sourceDescription='combine ( "PEEQ PI: PART-1-1 E: '+str(el_num)+' IP: 1", "S:Mises PI: PART-1-1 E: '+str(el_num)+' IP: 1" )')
tmpName = xy3.name
session.xyDataObjects.changeKey(tmpName, 'XYData-'+str(el_num))
xyp = session.XYPlot('XYPlot-'+str(el_num))
chartName = xyp.charts.keys()[0]
chart = xyp.charts[chartName]
xy1 = session.xyDataObjects['XYData-'+str(el_num)]
c1 = session.Curve(xyData=xy1)
chart.setValues(curvesToPlot=(c1, ), )
session.viewports['Viewport: 1'].setValues(displayedObject=xyp)
session.printToFile(fileneme='image'+str(el_num), format=TIFF,
canvasObjects=(session.viewports['Viewport:1'], ))


This is my script to reproduce element stress images from odb. After running i get key error.
KeyError: Viewport:1

Any help will be useful for me.

Thanks in advance