code: def _opref_for_op(op_name, model_ref):
      (pkg_type, pkg_name, pkg_version, model_name) = model_ref
      return OpRef(pkg_type, pkg_name, pkg_version, model_name, op_name)
  
file_path: guildai/guild/opref.py
imports: import collections
  import logging
  import os
  import re
  from guild import util
label_desc: Use image node_id 1 for calling a global function with example usage: _opref_for_op(op_name, model_ref) and returns: OpRef