code: def test_histogram():
      x = np.array(
          [0, 1, 1, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4], dtype="uintp"
      )
      h = histogram(x)
      assert_array_equal(h, [1, 2, 3, 4, 5])
  
imports: import numpy
  from numpy.testing import assert_array_equal
  from ..histogram import histogram
label_desc: Use image node_id 1 for calling a global function with example usage: test_histogram() without return types