code: def _get_x_class_instances(X, Y, label_class):
      if sp.issparse(Y):
          indices = Y[:, label_class].nonzero()[0]
      else:
          indices = np.nonzero(Y[:, label_class])[0]
      return X[indices, :]
  
file_path: scikit-multilearn/skmultilearn/adapt/mltsvm.py
imports: from skmultilearn.base import MLClassifierBase
  import numpy
  import scipy.sparse
  from scipy.linalg import norm
  from scipy.sparse.linalg import inv
  from scipy.linalg import inv
label_desc: Use image node_id 2 for calling a global function with example usage: _get_x_class_instances(X, Y, label_class) and returns: X