Removing # from header I have a $(418,2)$ matrix and I want to convert it to csv. so I write:

np.savetxt('titanic1.csv', Sol, fmt='%.2f', delimiter=",",header="PassengerId,Survived")


But the header I get is "# PassengerId" instead of "PassengerId" which is what I want. How can I solve this?
The documentation of numpy says you can add the parameter comments='', but warns that np.loadtxt() might not work on the resulting file.