Inversions

You are given a list that consists of the numbers $1 \dots n$. A pair of indices $(i,j)$ is an inversion if $i<j$ and the element at index $i$ on the list is greater than the element at index $j$.

You may assume that $n$ is at most $100$.

In a file inversions.py, implement a function count that returns the total number of inversions in the list.

def count(t):
    # TODO

if __name__ == "__main__":
    print(count([1,3,2])) # 1
    print(count([1])) # 0
    print(count([4,3,2,1])) # 6
    print(count([1,8,2,7,3,6,4,5])) # 12

Explanation: The list $[4,3,2,1]$ contains the inversions $(0,1)$, $(0,2)$, $(0,3)$, $(1,2)$, $(1,3)$ and $(2,3)$.