class_docstr: Tests for the eigvals_to_frequencies function
class_docstr_tok: ["Tests","for","the","eigvals_to_frequencies","function"]
docstr: Test the case of non-equidistant eigenvalues
code: def test_nonequidistant_eigvals(self):
      """Test the case of non-equidistant eigenvalues"""
      res = eigvals_to_frequencies((0.453, 0.65, -1.2, 0))
      expected = (0.453, 1.2, 1.85, 1.653, 0.65, 0.197)
      assert res == expected
  
imports: import pytest
  import numpy
  import pennylane
  from pennylane.gradients.general_shift_rules import eigvals_to_frequencies, frequencies_to_period, generate_shift_rule, _get_shift_rule, generate_multi_shift_rule, generate_shifted_tapes, generate_multishifted_tapes, _iterate_shift_rule_with_multipliers
label_desc: Use image node_id 3 for calling the TestEigvalsToFrequencies obj's underlying member method code with example usage: obj.test_nonequidistant_eigvals() without return types