class_docstr: The QM7b dataset of molecules from the paper:
  
  > [MoleculeNet: A Benchmark for Molecular Machine Learning](https://arxiv.org/abs/1703.00564)<br>
  > Zhenqin Wu et al.
  
  The dataset has no node features.
  Edges and edge features are obtained from the Coulomb matrices of the
  molecules.
  
  Each graph has a 14-dimensional label for regression.
code: def __init__(self, **kwargs):
      super().__init__(**kwargs)
  
file_path: spektral/spektral/datasets/qm7.py
imports: import os.path
  import numpy
  import scipy.sparse
  from scipy.io import loadmat
  from tensorflow.keras.utils import get_file
  from spektral.data import Dataset, Graph
  from spektral.utils import sparse
label_desc: Use image node_id 1 to create a new QM7 object from inherited base classes: Dataset with example: obj = QM7()