fixed add_cpd and get_cpd
fixed add_cpd and get_cpd

kislayabhi/pgmpy,pgmpy/pgmpy,pratyakshs/pgmpy,vivek425ster/pgmpy,liquidmetal/pgmpy,abinashpanda/pgmpy,jhonatanoliveira/pgmpy,vivek425ster/pgmpy,khalibartan/pgmpy,ankurankan/pgmpy,pgmpy/pgmpy,sandeepkrjha/pgmpy,pratyakshs/pgmpy,kislayabhi/pgmpy,jhonatanoliveira/pgmpy,kris-singh/pgmpy,kris-singh/pgmpy,palashahuja/pgmpy,anaviltripathi/pgmpy,palashahuja/pgmpy,liquidmetal/pgmpy,yashu-seth/pgmpy,khalibartan/pgmpy,sandeepkrjha/pgmpy,abinashpanda/pgmpy,yashu-seth/pgmpy,anaviltripathi/pgmpy,ankurankan/pgmpy