docs: def parse_collection(obj: dict) -> BioCCollection:
      """Deserialize a dict obj to a BioCCollection object"""
      collection = BioCCollection()
      collection.source = obj['source']
      collection.date = obj['date']
      collection.key = obj['key']
      collection.infons = obj['infons']
      for doc in obj['documents']:
          collection.add_document(parse_doc(doc))
      return collection