code: def conf_merger(user_dict, variable):
      
      if variable not in globals().keys():
          raise NameError("Unknown variable '%s'." % variable)
  
      if variable not in user_dict:
          return globals()[variable]
  
      return globals()[variable] and user_dict[variable]
docs: Merge global configuration with user's personal configuration.
  
      Global configuration has always higher priority.