code: def _dcm_array_to_matrix3(self, dcm):
          
          assert(dcm.shape == (3, 3))
          a = Vector3(dcm[0][0], dcm[0][1], dcm[0][2])
          b = Vector3(dcm[1][0], dcm[1][1], dcm[1][2])
          c = Vector3(dcm[2][0], dcm[2][1], dcm[2][2])
          return Matrix3(a, b, c)
docs: Converts dcm array into Matrix3
          :param dcm: 3x3 dcm array
          :returns: Matrix3