code: def test_is_square(self, mat, expected):
      res = Matrices.is_square(mat)
      self.assertAllEqual(res, expected)
  
imports: import pytest
  import geomstats.backend
  from geomstats.geometry.matrices import Matrices
  from geomstats.test.test_case import TestCase
  from geomstats.test.vectorization import generate_vectorization_data
  from geomstats.test_cases.geometry.base import MatrixVectorSpaceTestCase
  from geomstats.test_cases.geometry.euclidean import EuclideanMetricTestCase
label_desc: Use image node_id 19 for calling the MatrixOperationsTestCase obj's underlying member method code with example usage: obj.test_is_square(mat, expected) without return types