code: def _mnist_grid_graph(k):
      X = _grid_coordinates(MNIST_SIZE)
      A = _get_adj_from_data(
          X,
          k,
          mode="connectivity",
          metric="euclidean",
          include_self=False,
      )
  
      return A
  
file_path: spektral/spektral/datasets/mnist.py
imports: import numpy
  import scipy.sparse
  from sklearn.neighbors import kneighbors_graph
  from tensorflow.keras.datasets import mnist
  from spektral.data import Dataset, Graph
label_desc: Use image node_id 3 for calling a global function with example usage: _mnist_grid_graph(k) and returns: A