class_docstr: An object which handles communicating with metadata db through MLMD.
code: def get_completed_trials(self):
      return []
  
file_path: model_search/model_search/metadata/mock_metadata.py
imports: from model_search.metadata import metadata
label_desc: Use image node_id 3 for calling the MockMetaData obj's underlying member method code with example usage: obj.get_completed_trials() and returns: list