class_docstr: Retrieves Connection object and Variable from environment variable.
code: def get_conn_value(self, conn_id: str) -> str | None:
      return os.environ.get(CONN_ENV_PREFIX + conn_id.upper())
  
file_path: airflow/airflow/secrets/environment_variables.py
imports: from __future__ import annotations
  import os
  import warnings
  from airflow.exceptions import RemovedInAirflow3Warning
  from airflow.secrets import BaseSecretsBackend
label_desc: Use image node_id 2 for calling the EnvironmentVariablesBackend obj's underlying member method code with example usage: obj.get_conn_value(conn_id) and returns: os