code: def to_json(self):
      return {"filename": self.filename, "md5sum": self.md5sum}
  
imports: import hashlib
  import json
  import os
  import sqlalchemy
  from sqlalchemy.ext.declarative import declarative_base
  from sacred.dependencies import get_digest
  from sacred.serializer import restore
label_desc: Use image node_id 2 for calling the Source obj's underlying member method code with example usage: obj.to_json() and returns: dict