code: def fix_config(self, options):
          
          options = super(PRC, self).fix_config(options)
  
          opt = "class_index"
          if opt not in options:
              options[opt] = [0]
          if opt not in self.help:
              self.help[opt] = "The list of 0-based class-label indices to display (list)."
  
          opt = "key_loc"
          if opt not in options:
              options[opt] = "lower center"
          if opt not in self.help:
              self.help[opt] = "The location of the key in the plot (str)."
  
          opt = "title"
          if opt not in options:
              options[opt] = None
          if opt not in self.help:
              self.help[opt] = "The title for the plot (str)."
  
          opt = "outfile"
          if opt not in options:
              options[opt] = None
          if opt not in self.help:
              self.help[opt] = "The file to store the plot in (str)."
  
          opt = "wait"
          if opt not in options:
              options[opt] = True
          if opt not in self.help:
              self.help[opt] = "Whether to wait for user to close the plot window (bool)."
  
          return options
docs: Fixes the options, if necessary. I.e., it adds all required elements to the dictionary.
  
          :param options: the options to fix
          :type options: dict
          :return: the (potentially) fixed options
          :rtype: dict