code: def _zero_mean_function(x):
      return 0
  
file_path: pyro/pyro/contrib/gp/models/model.py
imports: import torch
  from pyro.contrib.gp.parameterized import Parameterized
label_desc: Use image node_id 1 for calling a global function with example usage: _zero_mean_function(x) and returns: int