code: def from_bytes(cls, key: bytes) -> bytes:
      ...
  
imports: from __future__ import annotations
  import base64
  import threading
  from abc import ABC, abstractmethod
  from cryptography import exceptions
  from cryptography.hazmat.primitives import hashes, serialization
  from cryptography.hazmat.primitives.asymmetric import padding, rsa
label_desc: Use image node_id 3 for calling the PublicKey obj's underlying member method code with example usage: obj.from_bytes(cls, key) without return types