To My Girlfriend

Dear Guo

I never forget the moment I met with you.You carefully asked me: "I have a very difficult problem. Can you teach me?".I replied with a smile, "of course"."I have n items, their weight was a[i]",you said,"Let's define f(i,j,k,l,m) to be the number of the subset of the weight of n items was m in total and has No.i and No.j items without No.k and No.l items.""And then," I asked.You said:"I want to know
$$
\sum_{i=1}^{n}\sum_{j=1}^{n}\sum_{k=1}^{n}\sum_{l=1}^{n}\sum_{m=1}^{s}f(i,j,k,l,m)\quad (i,j,k,l\quad are\quad different)
$$

Sincerely yours,
Liao

The first line of input contains an integer T$(T\le 15)$ indicating the number of test cases.
Each case contains 2 integers $n$, $s$ $(4\le n\le 1000,1\le s\le 1000)$. The next line contains n numbers: $a_1,a_2,\dots,a_n$ $(1\le a_i\le 1000)$.

Each case print the only number — the number of her would modulo $10^9+7$ (both Liao and Guo like the number).

2
4 4
1 2 3 4
4 4
1 2 3 4

8
8

UESTC

2016 Multi-University Training Contest 6