makes writer add xml header
makes writer add xml header

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