class_docstr: Tests for auxiliary functions to help with parsing
  Python function arguments
class_docstr_tok: ["Tests","for","auxiliary","functions","to","help","with","parsing","Python","function","arguments"]
docstr: Test _inv_dict correctly inverts a dictionary
docstr_tok: ["Test","_inv_dict","correctly","inverts","a","dictionary"]
code: def test_inv_dict(self):
      """Test _inv_dict correctly inverts a dictionary"""
      test_data = {"c": 8, "d": (0, 0.65), "e": "hi", "f": None, "g": 8}
      res = pu._inv_dict(test_data)
      expected = {
          8: {"g", "c"},
          (0, 0.65): {"d"},
          "hi": {"e"},
          None: {"f"},
      }
  
      assert res == expected
  
imports: import functools
  import itertools
  import pytest
  import numpy
  import pennylane
  import pennylane.utils
label_desc: Use image node_id 3 for calling the TestArgumentHelpers obj's underlying member method code with example usage: obj.test_inv_dict() without return types