code: def create_dir(self, params, delete=False):
          
          # create experiment path and subdir
          fullpath = os.path.join(params['path'], params['name'])
          self.mkdir(fullpath)
  
          # delete old histories if --del flag is active
          if delete and os.path.exists(fullpath):
              os.system('rm %s/*' % fullpath)
       
          # write a config file for this single exp. in the folder
          self.write_config_file(params, fullpath)
docs: creates a subdirectory for the experiment, and deletes existing
              files, if the delete flag is true. then writes the current
              experiment.cfg file in the folder.