code: def riemannian_submersion(point):
      return Matrices.mul(point, Matrices.transpose(point))
  
imports: import pytest
  import geomstats.backend
  from geomstats.geometry.fiber_bundle import FiberBundle
  from geomstats.geometry.matrices import Matrices
  from geomstats.geometry.special_orthogonal import SpecialOrthogonal
  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 2 for calling the GeneralLinearBuresWassersteinBundle obj's underlying member method code with example usage: obj.riemannian_submersion(point) and returns: Matrices