docs: static private int numOccurencesOfCharIn(String str, char ch) {
          boolean inMiddleOfQuote = false;
          int num = 0, previousIndex = 0;
          for (int index = str.indexOf(ch); index >= 0 ; index = str.indexOf(ch, index+1)) {
              if (hasOddNumberOfSingleQuotes(str.substring(previousIndex, index))) {
                  inMiddleOfQuote = !inMiddleOfQuote;
              }
              if (!inMiddleOfQuote) {
                  num++;
              }
              previousIndex = index;
          }
          return num;
      }