class_docstr: Creates params when fit is called on demand.
code: def make_importance_param(
      self, name="feature_importances_", value=None
  ):
      if value is None:
          value = np.random.rand(42)
      setattr(self, name, value)
  
imports: import pytest
  import numpy
  import numpy.testing
  import matplotlib.pyplot
  from yellowbrick.exceptions import NotFitted
  from yellowbrick.model_selection.importances import *
  from yellowbrick.datasets import load_occupancy, load_concrete
  from sklearn.datasets import load_iris
  from sklearn.ensemble import RandomForestClassifier
  from sklearn.ensemble import GradientBoostingClassifier
  from sklearn.base import BaseEstimator, ClassifierMixin
  from sklearn.linear_model import LogisticRegression, Lasso
  from sklearn.impute import SimpleImputer
  from sklearn.pipeline import Pipeline
  from unittest import mock
  from tests.base import VisualTestCase
label_desc: Use image node_id 1 for calling the MockEstimator obj's underlying member method code with example usage: obj.make_importance_param(name, value) without return types