The sign of the electron doesn't matter in this case. The definition of the direction of the current itself is also arbitrary. So are the definitions of positiv

The sign of the electron doesn't matter in this case. The definition of the direction of the current itself is also arbitrary. So are the definitions of positive and negative terminals. In fact, it is my understanding that most of the "left/right", "positive/negative", "north/south" definitions in EM are by convention. So the first guy calls it whatever they want and it doesn't matter at all.