code: def _gaussian_2d(shape, sigma=1):
      """Generate 2d gaussian.
  
      Parameters
      ----------
      shape : tuple of int
          The shape of the gaussian.
      sigma : float
          Sigma for gaussian.
  
      Returns
      -------
      float
          2D gaussian kernel.
  
      """
      m, n = [(ss - 1.0) / 2.0 for ss in shape]
      y, x = np.ogrid[-m : m + 1, -n : n + 1]
  
      h = np.exp(-(x * x + y * y) / (2 * sigma * sigma))
      h[h < np.finfo(h.dtype).eps * h.max()] = 0
      return h
  
file_path: gluon-cv/gluoncv/model_zoo/center_net/target_generator.py
imports: from __future__ import absolute_import
  import numpy
  from mxnet import nd
  from mxnet import gluon
label_desc: Use image node_id 2 for calling a global function with example usage: _gaussian_2d(shape, sigma) and returns: h