class_docstr: Dataset for Annotations used in MMF
  
  TODO: Update on docs sprint
code: def _load_npy(self, path):
      with PathManager.open(path, "rb") as f:
          self.db = np.load(f, allow_pickle=True)
  
      self.start_idx = 0
  
      if type(self.db) == dict:
          self.metadata = self.db.get("metadata", {})
          self.data = self.db.get("data", [])
      else:
          # TODO: Deprecate support for this
          self.metadata = {"version": 1}
          self.data = self.db
          # Handle old imdb support
          if "image_id" not in self.data[0]:
              self.start_idx = 1
  
      if len(self.data) == 0:
          self.data = self.db
  
file_path: mmf/mmf/datasets/databases/annotation_database.py
imports: import json
  import numpy
  import torch
  from mmf.utils.file_io import PathManager
  from mmf.utils.general import get_absolute_path
label_desc: Use image node_id 4 for calling the AnnotationDatabase obj's underlying member method code with example usage: obj._load_npy(path) without return types