new_contents: public class Solution {
      public boolean isValid(String s) {
          HashMap<Character, Character> pairs = new HashMap<Character, Character>();
          pairs.put('(', ')');
          pairs.put('[', ']');
          pairs.put('{', '}');
          
          Stack<Character> stack = new Stack<Character>();
          
          for (int i = 0; i < s.length(); i++) {
              char c = s.charAt(i);
              
              if (pairs.containsKey(c)) {
                  stack.push(c);
              } else {
                  if (stack.empty()) {
                      return false;
                  } else {
                      char t = stack.pop();
                      if (pairs.get(t) != c) {
                          return false;
                      }
                  }
              }
          }
          
          if (stack.empty()) {
              return true;
          }
          
          return false;
      }
  }
  
subject: Create ValParent_002.py