pygame sprite wall collision

Question

I am working on a platform game in python and pygame. The entire code can be found at \"https://github.com/C-Kimber/FBLA_Game\". The issue I am having is with the collision

Answer 1

elif self.rect.top <= block.rect.bottom and self.rect.top >= block.rect.bottom - 15:  # Moving up; Hit the bottom side of the wall
        self.rect.top = block.rect.bottom
        self.yvel = 0

Shouldn't yvel be set to a positive number to make it go up?