class_docstr: Tests allowable data formats when constructing
  the basic Element types.
class_docstr_tok: ["Tests","allowable","data","formats","when","constructing","the","basic","Element","types","."]
code: def test_pre_and_postprocess_hooks(self):
      pre_backup = operation._preprocess_hooks
      post_backup = operation._postprocess_hooks
      operation._preprocess_hooks = [lambda op, x: {"label": str(x.id)}]
      operation._postprocess_hooks = [
          lambda op, x, **kwargs: x.clone(**kwargs)
      ]
      curve = Curve([1, 2, 3])
      self.assertEqual(operation(curve).label, str(curve.id))
      operation._preprocess_hooks = pre_backup
      operation._postprocess_hooks = post_backup
  
imports: import datetime
  from unittest import skipIf
  import numpy
  import pandas
  import pytest
  from holoviews import Area, Contours, Curve, Dataset, GridSpace, Histogram, HoloMap, Image, NdLayout, NdOverlay, Points, Polygons, QuadMesh, renderer
  from holoviews.core.data.grid import GridInterface
  from holoviews.element.comparison import ComparisonTestCase
  from holoviews.operation.element import contours, decimate, gradient, histogram, interpolate_curve, operation, threshold, transform
label_desc: Use image node_id 54 for calling the OperationTests obj's underlying member method code with example usage: obj.test_pre_and_postprocess_hooks() without return types