#include <iostream>
#include <vector>
#include <algorithm>
 
using namespace std;
 
const long long MOD = 1000000007;
 
long long max_sum_after_operations(int n, int k, vector<int>& arr) {
    vector<long long> prefix_sum(n + 1, 0);
    for (int i = 0; i < n; ++i) {
        prefix_sum[i + 1] = prefix_sum[i] + arr[i];
    }
 
    long long max_sum = numeric_limits<long long>::min();
    for (int i = 0; i < n; ++i) {
        for (int j = i + 1; j <= n; ++j) {
            long long subarray_sum = prefix_sum[j] - prefix_sum[i];
            max_sum = max(max_sum, subarray_sum);
        }
    }
 
    max_sum += max_sum * (k - 1);
    return max_sum % MOD;
}
 
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
 
    int t;
    cin >> t;  // Number of test cases
    while (t--) {
        int n, k;
        cin >> n >> k;  // Length of the array and number of operations
        vector<int> arr(n);
        for (int i = 0; i < n; ++i) {
            cin >> arr[i];  // Array elements
        }
        cout << max_sum_after_operations(n, k, arr) << endl;  // Output result
    }
 
    return 0;
}
 

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