code: def mnist(limit=5000):
      pytest.importorskip("ml_datasets")
      import ml_datasets
  
      (train_X, train_Y), (dev_X, dev_Y) = ml_datasets.mnist()
      return (train_X[:limit], train_Y[:limit]), (
          dev_X[:limit],
          dev_Y[:limit],
      )
  
file_path: thinc/thinc/tests/layers/test_mnist.py
imports: import pytest
  from thinc.api import Adam, PyTorchWrapper, Relu, Softmax, TensorFlowWrapper, chain, clone, get_current_ops
  from thinc.compat import has_tensorflow, has_torch
label_desc: Use image node_id 1 for calling a global function with example usage: mnist(limit) and returns: train_X,  train_Y,  dev_X,  dev_Y