class_docstr: Test for validation and exceptions
docstr: Test that an error is raised if the transform
  is applied to an invalid function
docstr_tok: ["Test","that","an","error","is","raised","if","the","transform","is","applied","to","an","invalid","function"]
code: def test_error_invalid_callable(self):
      """Test that an error is raised if the transform
      is applied to an invalid function"""
  
      with pytest.raises(
          OperationTransformError,
          match="does not appear to be a valid Python function",
      ):
          qml.op_transform(5)
  
imports: import pytest
  import pennylane
  from pennylane import numpy
  from pennylane.transforms.op_transforms import OperationTransformError
label_desc: Use image node_id 2 for calling the TestValidation obj's underlying member method code with example usage: obj.test_error_invalid_callable() without return types