class_docstr: Test the pauli_sentence function.
docstr: Test that a ValueError is raised when trying to cast operators to a PauliSentence
  which are not linear combinations of Pauli words.
docstr_tok: ["Test","that","a","ValueError","is","raised","when","trying","to","cast","operators","to","a","PauliSentence","which","are","not","linear","combinations","of","Pauli","words","."]
code: def test_error_not_linear_comb_pauli_words(self, op):
      """Test that a ValueError is raised when trying to cast operators to a PauliSentence
      which are not linear combinations of Pauli words."""
      with pytest.raises(
          ValueError,
          match="Op must be a linear combination of Pauli operators only, got:",
      ):
          pauli_sentence(op)
  
imports: import pytest
  import numpy
  import pennylane
  from pennylane.operation import Tensor
  from pennylane.ops import Identity, PauliX, PauliY, PauliZ
  from pennylane.pauli import pauli_sentence, PauliWord, PauliSentence
  from pennylane.pauli.conversion import _generalized_pauli_decompose
label_desc: Use image node_id 7 for calling the TestPauliSentence obj's underlying member method code with example usage: obj.test_error_not_linear_comb_pauli_words(op) without return types