code: int getNumBranches(int lineNumber) {
      Integer numBranches = branchesInLine.get(lineNumber - 1);
      if (numBranches == null) {
        return 0;
      } else {
        return numBranches;
      }
    }
docs: Get the number of branches on a line
  @param lineNumber - the 1-based line number
  @return the number of branches on the line.