Define the alternating sum of an array (b) of length (k) to be (\sum_{i = 1}^{k}(-1)^{i+1}b_i). You are given a non-decreasing(^{\text{∗}}) array (a) of length (n) such that for all (1 \le i \le n,) either (a_i = -1) or (a_i) is a positive integer. Find the number of sequences (1 \le i_1 \lt i_2 \lt \ldots \lt i_k \le n) such that the alternating sum of the sequence (a_{i_1}, a_{i_2}, \ldots, a_{i_k}) is (0.) Since this number may be large, output it modulo (10^9+7). Two sets (i_1, \ldots, i_{k_1}) and (i'_1, \ldots, i'_{k_2}) of indices are considered different if (k_1 \neq k_2) or there exists a (j) such that (i_j \neq i'_j.) (^{\text{∗}})A sequence (a_1, \ldots, a_n) is non-decreasing if (a_1 \le a_2 \le \ldots \le a_n). Each test contains multiple test cases. The first line contains the number of test cases (t) ((1 \le t \le 10^4)). The description of the test cases follows. The first line of each test case contains a single integer (n \, (1 \le n \le 2 \cdot 10^5)) — the length of the array. The second line of each test case contains (n) integers (a_1, a_2, \ldots, a_n) — the elements of the array where (\mathbf{a_i = -1}) or (\mathbf{1 \leq a_i \leq 10^9}). It is guaranteed that the array is non-decreasing. It is guaranteed that the sum of (n) over all test cases does not exceed (2 \cdot 10^5). For each testcase, output a single integer — the number of subsequences that have an alternating sum of zero modulo (10^9 +7). A subsequence of length (0) is considered to have an alternating sum of zero. In the first example, the following subsequences have an alternating sum of zero: (\bullet) ([],) (\bullet) (a_2,a_3 = 1,1), (\bullet) (a_1, a_2, a_4 = -1,1,2), (\bullet) (a_1, a_3, a_4 = -1,1,2), (\bullet) (a_1, a_4, a_5 = -1,2,3), (\bullet) $$$a_1,a_2,a_3,a_4,a_5 = [-1,1