class_docstr: Diffeomorphism between S1 and SO2.
class_docstr_tok: ["Diffeomorphism","between","S1","and","SO2","."]
code: def inverse_diffeomorphism(self, image_point):
      return image_point[..., 0]
  
imports: import pytest
  import geomstats.backend
  from geomstats.geometry.diffeo import AutodiffDiffeo
  from geomstats.test.random import RandomDataGenerator
  from geomstats.test.test_case import TestCase
  from geomstats.test.vectorization import generate_vectorization_data
label_desc: Use image node_id 3 for calling the CircleSO2Diffeo obj's underlying member method code with example usage: obj.inverse_diffeomorphism(image_point) and returns: image_point