code: public Comment addDiscussionComment(long id, Comment comment) throws SmartsheetException {
          return this.createResource("discussion/" + id + "/comments", Comment.class, comment);
      }
docs: Add a comment to a discussion.
  
  It mirrors to the following Smartsheet REST API method: POST /discussion/{discussionId}/comments
  
  Exceptions:
  IllegalArgumentException : if any argument is null
  InvalidRequestException : if there is any problem with the REST API request
  AuthorizationException : if there is any problem with the REST API authorization(access token)
  ServiceUnavailableException : if the REST API service is not available (possibly due to rate limiting)
  SmartsheetRestException : if there is any other REST API related error occurred during the operation
  SmartsheetException : if there is any other error occurred during the operation
  
  @param id the discussion ID
  @param comment the comment to add, limited to the following required attributes: text
  @return the created comment
  @throws SmartsheetException the smartsheet exception