code: def close_plt(params):
      if params.get("engine", "plotly") == "matplotlib":
          matplotlib.pyplot.close()
  
imports: import pytest
  import joblib
  import os
  import json
  import numpy
  import pandas
  from itertools import product
  import matplotlib
  from abc import ABC, abstractmethod
  import warnings
label_desc: Use image node_id 2 for calling the PlotTestBase obj's underlying member method code with example usage: obj.close_plt(params) without return types