code: def to_json(self):
      return "{}=={}".format(self.name, self.version or "<unknown>")
  
imports: import functools
  import hashlib
  import os.path
  import re
  import sys
  from pathlib import Path
  import pkg_resources
  import sacred.optional
  from sacred import SETTINGS
  from sacred.utils import iter_prefixes
label_desc: Use image node_id 3 for calling the PackageDependency obj's underlying member method code with example usage: obj.to_json() and returns: str