I feel as if my code should not have any problems, but an error keeps popping up saying “burls” is not defined. Here is my code:

```
# Senick is trying to find the elusive Burleous Majoris!
# But he doesn't know how big a Burleous Majoris would be...
# Find the average size of this burl population to use as a baseline!
# This function returns average size of all the burls in an array.
def averageSize(burls):
sum = sumSize(burls)
# Remember the average is the sum of the parts divided by the amount!
return sum / burls.length
# This function should return the sum of all the burls sizes.
def sumSize(burls):
# Implement the sum function using the burls 'size'
sum = 0
for burl in burls:
sum = sum + burl.size
while True:
# Find the average size of the burls by calling the 'averageSize' function.
averageSize()
# Say the average size of the seen burls!
hero.say(averageSize())
```