code: def _set_tk_config(self, keys, value):
          
  
          # if a single key is passed, convert to list
          if isinstance(keys, str):
              keys = [keys]
  
          # loop through all the keys
          for key in keys:
              if key in self.tk.keys():
                  if value is None:
                      # reset to default
                      self.tk[key] = self._tk_defaults[key]
                  else:
                      self.tk[key] = value
docs: Gets the config from the widget's tk object
  
          :param string/List keys:
              The tk config key or a list of tk keys.
  
          :param variable value:
              The value to set. If the value is `None`, the config value will be
              reset to its default.