class_docstr: Test class for scipy.stats.variation
code: def test_keepdims_and_ddof_eq_len_plus_incr(
      self, incr, expected_fill
  ):
      x = np.array([[1, 1, 2, 2], [1, 2, 3, 3]])
      y = variation(x, axis=1, ddof=x.shape[1] + incr, keepdims=True)
      assert_equal(y, np.full((2, 1), fill_value=expected_fill))
  
imports: import numpy
  from numpy.testing import assert_equal, assert_allclose
  import pytest
  from scipy.stats import variation
  from scipy._lib._util import AxisError
label_desc: Use image node_id 9 for calling the TestVariation obj's underlying member method code with example usage: obj.test_keepdims_and_ddof_eq_len_plus_incr(incr, expected_fill) without return types