code: def process_kwargs(self, kwargs, prefix='default_', delete=True):
          
          processed = []
          for k in kwargs:
              if hasattr(self, prefix + k):
                  processed += [k]
                  setattr(self, prefix + k, kwargs[k])
          for k in processed:
              del(kwargs[k])
          return kwargs
docs: set self attributes based on kwargs, optionally deleting kwargs that are processed