code: def __getitem__(self, key):
      if isinstance(key, str):
          key = key.encode("utf-8")
      self._verify_open()
      pos, siz = self._index[key]  # may raise KeyError
      with _io.open(self._datfile, "rb") as f:
          f.seek(pos)
          dat = f.read(siz)
      return dat
  
imports: import ast
  import io
  import os
  import collections.abc
label_desc: Use image node_id 6 for calling the _Database obj's underlying member method code with example usage: obj.__getitem__(key) and returns: dat