code: def test_package_dependency_fill_missing_version_unknown():
      pd = PackageDependency("mymod", None)
      pd.fill_missing_version()
      assert pd.version == None
  
imports: import os.path
  import os
  from pathlib import Path
  import mock
  import pytest
  from sacred.dependencies import PEP440_VERSION_PATTERN, PackageDependency, Source, gather_sources_and_dependencies, get_digest, get_py_file_if_possible, is_local_source
  import sacred.optional
label_desc: Use image node_id 14 for calling a global function with example usage: test_package_dependency_fill_missing_version_unknown() without return types