code: def _count_nonzero_coefficients(estimator):
      a = estimator.coef_.toarray()
      return np.count_nonzero(a)
  
file_path: scikit-learn/examples/applications/plot_model_complexity_influence.py
imports: import time
  import matplotlib.pyplot
  import numpy
  from sklearn import datasets
  from sklearn.ensemble import GradientBoostingRegressor
  from sklearn.linear_model import SGDClassifier
  from sklearn.metrics import hamming_loss, mean_squared_error
  from sklearn.model_selection import train_test_split
  from sklearn.svm import NuSVR
label_desc: Use image node_id 3 for calling a global function with example usage: _count_nonzero_coefficients(estimator) and returns: np