code: def get_customjs(self, references, plot_id=None):
          
          # Generate callback JS code to get all the requested data
          if plot_id is None:
              plot_id = self.plot.id or 'PLACEHOLDER_PLOT_ID'
          self_callback = self.js_callback.format(comm_id=self.comm.id,
                                                  timeout=self.timeout,
                                                  debounce=self.debounce,
                                                  plot_id=plot_id)
  
          attributes = self.attributes_js(self.attributes)
          conditions = ["%s" % cond for cond in self.skip]
          conditional = ''
          if conditions:
              conditional = 'if (%s) { return };\n' % (' || '.join(conditions))
          data = "var data = {};\n"
          code = conditional + data + attributes + self.code + self_callback
          return CustomJS(args=references, code=code)
docs: Creates a CustomJS callback that will send the requested
          attributes back to python.