func_code_string: #include <bits/stdc++.h>   using namespace std;   long long MOD = 1e9 + 7;   long long FastPower(long long x, long long y) {     long long res = 1;     x = x % MOD;     while (y > 0) {       if (y & 1) res = (res * x) % MOD;       y = y >> 1;       x = (x * x) % MOD;     }     return res;   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     long long n, k;     string s;     cin >> s;     n = s.size();     long long x = 0, y = 0;     y = FastPower(2, n - 1);     for (int i = 0, j = n - 1; i < n; i++, j--) {       if (s[j] ==  1 ) {         x += FastPower(2, i);         x %= MOD;       }     }     cout << (x * y) % MOD;     return 0;   }   