class_docstr: concat Eigen features
  
  Notes
  -----
  An implementation of [#]_
  
  References
  ----------
  .. [#] Z. Zhang, P. Cui, J. Pei, X. Wang and W. Zhu,
          "Eigen-GNN: a Graph Structure Preserving Plug-in for GNNs,"
          in IEEE Transactions on Knowledge and Data Engineering, doi: 10.1109/TKDE.2021.3112746.
  
  Parameters
  ----------
  size : int
      EigenGNN hidden size
code: def __init__(self, size: int = 32):
      super(EigenFeatureGenerator, self).__init__()
      self.__size: int = size
  
file_path: AutoGL/autogl/module/preprocessing/feature_engineering/_generators/_eigen.py
imports: import autogl
  import numpy
  from scipy.sparse import csr_matrix
  import scipy.sparse
  import scipy.sparse.linalg
  import networkx
  import torch
  from ._basic import BaseFeatureGenerator
  from ..._data_preprocessor_registry import DataPreprocessorUniversalRegistry
label_desc: Use image node_id 1 to create a new EigenFeatureGenerator object from inherited base classes: BaseFeatureGenerator with example: obj = EigenFeatureGenerator(size)