code: def test_0d(self):
      # gh-580
      x = np.unravel_index(0, ())
      assert_equal(x, ())
  
      assert_raises_regex(
          ValueError, "0d array", np.unravel_index, [0], ()
      )
      assert_raises_regex(
          ValueError, "out of bounds", np.unravel_index, [1], ()
      )
  
imports: import pytest
  import numpy
  from numpy.testing import assert_, assert_equal, assert_array_equal, assert_almost_equal, assert_array_almost_equal, assert_raises, assert_raises_regex
  from numpy.lib.index_tricks import mgrid, ogrid, ndenumerate, fill_diagonal, diag_indices, diag_indices_from, index_exp, ndindex, r_, s_, ix_
label_desc: Use image node_id 7 for calling the TestRavelUnravelIndex obj's underlying member method code with example usage: obj.test_0d() without return types