Chapter 5. Statistics, median function

the median function raise "IndexError" while pass an empty list as an argument to function.

place this lines correct the issue:

elif n == 0: return "The list is empty"

else:
    # if even, return the average of the middle values
    lo = midpoint - 1
    hi = midpoint
    return (sorted_v[lo] + sorted_v[hi]) / 2