add python3tutorial.md
add python3tutorial.md

SilverRainZ/notes,LastAvenger/notes,LastAvenger/no-silver-bullet,SilverRainZ/notes,SilverRainZ/notes,LastAvenger/tqybtmyaath,LastAvenger/tqybtmyaath,LastAvenger/no-silver-bullet,LastAvenger/notes,LastAvenger/no-silver-bullet