code: public Folder createFolder(long workspaceId, Folder folder) throws SmartsheetException {
          return this.createResource("workspaces/" + workspaceId + "/folders", Folder.class, folder);
      }
docs: Create a folder in the workspace.
  
  It mirrors to the following Smartsheet REST API method: POST /workspace/{id}/folders
  
  Exceptions:
  - IllegalArgumentException : if folder 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 workspaceId the workspace id
  @param folder the folder to create
  @return the created folder
  @throws SmartsheetException the smartsheet exception