fixes index order issue https://github.com/pgmpy/pgmpy/pull/541#issuecomment-164745151
fixes index order issue https://github.com/pgmpy/pgmpy/pull/541#issuecomment-164745151

abinashpanda/pgmpy,liquidmetal/pgmpy,pgmpy/pgmpy,kris-singh/pgmpy,abinashpanda/pgmpy,anaviltripathi/pgmpy,khalibartan/pgmpy,khalibartan/pgmpy,sandeepkrjha/pgmpy,ankurankan/pgmpy,liquidmetal/pgmpy,jhonatanoliveira/pgmpy,pgmpy/pgmpy,sandeepkrjha/pgmpy,anaviltripathi/pgmpy,ankurankan/pgmpy,jhonatanoliveira/pgmpy,kris-singh/pgmpy