class_docstr: A protocol defining the interface for an artifact backend.
  
  An artifact backend is responsible for managing the storage and retrieval
  of artifact data. The backend should provide methods for opening, writing
  and removing artifacts.
docstr: Open the artifact identified by the artifact_id.
  
  This method should return a binary file-like object in read mode, similar to
  ``open(..., mode="rb")``. If the artifact does not exist, an
  :exc:`~optuna.artifacts.exceptions.ArtifactNotFound` exception
  should be raised.
  
  Args:
      artifact_id: The identifier of the artifact to open.
  
  Returns:
      BinaryIO: A binary file-like object that can be read from.
docstr_tok: ["Open","the","artifact","identified","by","the","artifact_id",".","This","method","should","return","a","binary","file-like","object","in","read","mode",",","similar","to","``","open","(","...",",","mode=","''","rb","''",")","``",".","If","the","artifact","does","not","exist",",","an",":","exc",":","`","~optuna.artifacts.exceptions.ArtifactNotFound","`","exception","should","be","raised",".","Args",":","artifact_id",":","The","identifier","of","the","artifact","to","open",".","Returns",":","BinaryIO",":","A","binary","file-like","object","that","can","be","read","from","."]
code: def open_reader(self, artifact_id: str) -> BinaryIO:
      """Open the artifact identified by the artifact_id.
  
      This method should return a binary file-like object in read mode, similar to
      ``open(..., mode="rb")``. If the artifact does not exist, an
      :exc:`~optuna.artifacts.exceptions.ArtifactNotFound` exception
      should be raised.
  
      Args:
          artifact_id: The identifier of the artifact to open.
  
      Returns:
          BinaryIO: A binary file-like object that can be read from.
      """
      ...
  
imports: from __future__ import annotations
  from typing import TYPE_CHECKING
label_desc: Use image node_id 1 for calling the ArtifactStore obj's underlying member method code with example usage: obj.open_reader(artifact_id) without return types