code: def make_test_vstack_data():
      a = np.array([[1], [2], [3]])
      b = np.array([[2], [3], [4]])
      empty = np.array([], np.int64).reshape((0, 1))
  
      yield a, b
      yield a, empty, b
      yield empty, a, b
  
      a = np.array([1, 2, 3])
      b = np.array([2, 3, 4])
      yield a, b
  
imports: import math
  import numpy
  import re
  from ..helpers import *
  import pytest
  from hail.utils.java import FatalError, HailUserError
label_desc: Use image node_id 36 for calling a global function with example usage: make_test_vstack_data() without return types