code: def Rt_to_matrix4x4(R: Tensor, t: Tensor) -> Tensor:
      r"""Combines 3x3 rotation matrix R and 1x3 translation vector t into 4x4 extrinsics.
  
      Args:
          R: Rotation matrix, :math:`(B, 3, 3).`
          t: Translation matrix :math:`(B, 3, 1)`.
  
      Returns:
          the extrinsics :math:`(B, 4, 4)`.
  
      Example:
          >>> R, t = torch.eye(3)[None], torch.ones(3).reshape(1, 3, 1)
          >>> Rt_to_matrix4x4(R, t)
          tensor([[[1., 0., 0., 1.],
                   [0., 1., 0., 1.],
                   [0., 0., 1., 1.],
                   [0., 0., 0., 1.]]])
      """
      KORNIA_CHECK_SHAPE(R, ["B", "3", "3"])
      KORNIA_CHECK_SHAPE(t, ["B", "3", "1"])
      Rt = concatenate([R, t], dim=2)
      return convert_affinematrix_to_homography3d(Rt)
  
imports: from __future__ import annotations
  from typing import Optional
  import torch
  import torch.nn.functional
  from kornia.constants import pi
  from kornia.core import Tensor, concatenate, cos, pad, sin, stack, tensor, where, zeros_like
  from kornia.core.check import KORNIA_CHECK, KORNIA_CHECK_SHAPE
  from kornia.utils import deprecated
  from kornia.utils.helpers import _torch_inverse_cast
label_desc: Use image node_id 37 for calling a global function with example usage: Rt_to_matrix4x4(R, t) and returns: convert_affinematrix_to_homography3d