code: def batch_diagonal(
      F,
      matrix: Tensor,
      num_data_points: Optional[int] = None,
      float_type=np.float32,
  ) -> Tensor:
      """
      This function extracts the diagonal of a batch matrix.
  
      Parameters
      ----------
      F
          A module that can either refer to the Symbol API or the NDArray
          API in MXNet.
      matrix
          matrix of shape (batch_size, num_data_points, num_data_points).
      num_data_points
          Number of rows in the kernel_matrix.
  
      Returns
      -------
      Tensor
          Diagonals of kernel_matrix of shape (batch_size, num_data_points, 1).
      """
      return F.linalg.gemm2(
          F.broadcast_mul(
              F.eye(num_data_points, dtype=float_type), matrix
          ),
          F.ones_like(F.slice_axis(matrix, axis=2, begin=0, end=1)),
      )
  
imports: from typing import Optional, Type
  import mxnet
  import numpy
  from gluonts.mx import Tensor
label_desc: Use image node_id 1 for calling a global function with example usage: batch_diagonal(F, matrix, num_data_points, float_type) and returns: F