ImportError: No module named ROOT

Hi,

  I am trying to run python script (file attached) locally (not on lxplus), but when I give the command :

$> python plot_hlt_studies_all.py Histos_oldtk.root

error message comes :

Traceback (most recent call last):
  File "plot_hlt_studies_all.py", line 2, in ?     import ROOT
ImportError: No module named ROOT

Please guide me how to remedy this error.

regards,
Supreet