code: def transform_coors(self, mtx_t, ref_coors=None):
          
          if ref_coors is None:
              ref_coors = self.coors
  
          if mtx_t.shape[1] > self.coors.shape[1]:
              self.coors[:] = nm.dot(ref_coors, mtx_t[:,:-1].T) + mtx_t[:,-1]
          else:
              self.coors[:] = nm.dot(ref_coors, mtx_t.T)
docs: Transform coordinates of the mesh by the given transformation matrix.
  
          Parameters
          ----------
          mtx_t : array
             The transformation matrix `T` (2D array). It is applied
             depending on its shape:
  
             - `(dim, dim): x = T * x`
             - `(dim, dim + 1): x = T[:, :-1] * x + T[:, -1]`
          ref_coors : array, optional
             Alternative coordinates to use for the transformation instead
             of the mesh coordinates, with the same shape as `self.coors`.