player_y = 100
vel = 0 # Velocity
jumping_state = False
player_y += vel
# Let's say something happends (like a key input) and jumping_state is True
def gravity(vel):
if jumping_state:
player_y = player_y - 20 # How high the player jumps
vel += 0.1 # Or a different value
jumping_state = False
gravity(vel)