class_docstr: A dataset with many graphs and node-level labels
code: def read(self):
      return [
          Graph(
              x=np.random.rand(n, f),
              a=sp.csr_matrix(np.random.randint(0, 2, (n, n))),
              e=np.random.rand(n, n, s),
              y=np.ones((n, 2)),
          )
          for n in ns
      ]
  
imports: import numpy
  import scipy.sparse
  from spektral.data import BatchLoader, DisjointLoader
  from spektral.data.dataset import Dataset
  from spektral.data.graph import Graph
  from spektral.data.loaders import MixedLoader, PackedBatchLoader, SingleLoader
label_desc: Use image node_id 1 for calling the TestDatasetDsjNode obj's underlying member method code with example usage: obj.read() and returns: unknown