code: def gaussian_gradient(x: float, mean: float, var: float) -> float:
      """Analytically evaluate Gaussian gradient."""
      gradient = (mean - x) / (var**2)
      return gradient
  
imports: import random
  import numpy
  import pytest
  import stan
label_desc: Use image node_id 1 for calling a global function with example usage: gaussian_gradient(x, mean, var) and returns: gradient