How can I convert a model matrix to look at matrix

[MeyerBuaharon]

I am using open3d for my project, and it uses opengl for his visualiztion.

I am trying to understand how can I get my current model_matrix, save it on an ini file, and load it with a look_at function that they use.

now, get_model_matrix is:

get_model_matrix(self: open3d.cpu.pybind.visualization.rendering.Camera) → numpy.ndarray[numpy.float32[4, 4]]
Returns the model matrix of the camera

and look_at` function is:

look_at(self: open3d.cpu.pybind.visualization.rendering.Camera, arg0: numpy.ndarray[numpy.float32[3, 1]], arg1: numpy.ndarray[numpy.float32[3, 1]], arg2: numpy.ndarray[numpy.float32[3, 1]]) → None
Sets the position and orientation of the camera: look_at(center, eye, up)

so in the end what I want is to get the matrix from the get_model_matrix which returns a 4x4 shape, and convert it to [center, eye, up].

If anyone is familiar with it and can tell me how I can convert I would appreciate it.

Example:
For look_at

      self.center = [21, -30, -31]
      self.eye = [10, -26, -27]
      self.up = [1, 1, 1]

the get_model_matrix:

[[  0.           0.45732954  -0.88929725  10.        ]
 [ -0.70710677   0.6288281    0.32338083 -26.        ]
 [  0.70710677   0.6288281    0.32338083 -27.        ]
 [  0.           0.           0.           1.        ]]

For example, I can figure out that the eye column is the same as the last column in the model_matrix, but I can't understand the rest...