I need help when i play then this happens:

here is my code:

```
#Mirror your partner's movement around the center X mark.
# Vectors can be thought of as an x, y position
# Vectors can also represent the distance and direction between two positions
# use Vector.subtract(vector1, vector2) to find the direction and distance from vector2 to vector1
# use Vector.add(vector1, vector2) to find the position you get when you start from vector1 and follow vector2
# A unit's position is actually a Vector!
partner = hero.findByType("peasant")[0]
Vector.subtract(partner.pos, hero.pos)
Vector.add(hero.pos, partner.pos)
# Create a new Vector at the center X point
center = Vector(40, 34)
while True:
# First, you want to find the Vector (distance and direction) of the partner's position to the center X.
vector = Vector.subtract(center,partner.pos)
# Second, find the position your hero should moveTo starting from center, and following vector.
moveToPos = Vector.add(vector, center - vector)
# Third, move to the moveToPos position.
hero.move(moveToPos)
pass
```