code: def act(self):
          
          g = get_root(self).globals
          fname = filedialog.askopenfilename(
              defaultextension='.json',
              filetypes=[('json files', '.json'), ('fits files', '.fits')],
              initialdir=g.cpars['app_directory'])
          if not fname:
              g.clog.warn('Aborted load from disk')
              return False
  
          # load json
          if fname.endswith('.json'):
              with open(fname) as ifname:
                  json_string = ifname.read()
          else:
              json_string = jsonFromFits(fname)
  
          # load up the instrument settings
          g.ipars.loadJSON(json_string)
  
          # load up the run parameters
          g.rpars.loadJSON(json_string)
  
          return True
docs: Carries out the action associated with the Load button