code: def _mk_group(group_dict):
      return list(
          chain(
              *[
                  [k + "::" + v for v in files]
                  for k, files in group_dict.items()
              ]
          )
      )
  
file_path: sympy/conftest.py
imports: from __future__ import print_function, division, absolute_import
  import os
  from itertools import chain
  import json
  import sys
  import warnings
  import pytest
  from sympy.testing.runtests import setup_pprint, _get_doctest_blacklist
label_desc: Use image node_id 1 for calling a global function with example usage: _mk_group(group_dict) and returns: list