code: def _addval(self, val):
      with _io.open(self._datfile, "rb+") as f:
          f.seek(0, 2)
          pos = int(f.tell())
          npos = ((pos + _BLOCKSIZE - 1) // _BLOCKSIZE) * _BLOCKSIZE
          f.write(b"\0" * (npos - pos))
          pos = npos
          f.write(val)
      return (pos, len(val))
  
imports: import ast
  import io
  import os
  import collections.abc
label_desc: Use image node_id 7 for calling the _Database obj's underlying member method code with example usage: obj._addval(val) and returns: pos,  len