docs: public void addCategory(IssueCategory category) throws DuplicateIssueCategoryException
      {
          IssueCategory original = this.issueCategories.get(category.getCategoryID());
  
          // Just overwrite it if it was a placeholder
          if (original != null && !original.isPlaceholder())
          {
              StringBuilder message = new StringBuilder("Issue category (ID: ").append(category.getCategoryID())
                          .append(") is defined at the following locations:");
              message.append(OperatingSystemUtils.getLineSeparator());
              message.append("\t1: " + original.getOrigin());
              message.append("\t2: " + category.getOrigin());
  
              throw new DuplicateIssueCategoryException(message.toString());
          }
  
          this.issueCategories.put(category.getCategoryID(), category);
      }