[ndnSIM] problem in building ndnSIM 2.7

[Swetha]

Hello

I am new to ndnSIM and have problem with building ndnSIM 2.7

I followed steps as per the link 
https://ndnsim.net/current/getting-started.html

when i am trying to build using command ./waf I am getting error below. 
Please help



[3105/3246] Compiling build/src/visualizer/visualizer/base.pyc
Traceback (most recent call last):
   File "<string>", line 3, in <module>
   File "/usr/lib/python2.7/py_compile.py", line 117, in compile
     raise py_exc
py_compile.PyCompileError:   File 
"/usr/local/lib/python2.7/dist-packages/visualizer/base.py", line 134
     print("Could not load plugin %r: %s" % (filename, str(ex)), 
file=sys.stderr)
                                                                     ^
SyntaxError: invalid syntax


Waf: Leaving directory `/home/swetha/ndnSIM/ns-3/build'
Build failed
  -> task in '' failed with exit status 1 (run with -v to display more 
information)



Thanks

Swetha B