class_docstr: Base test class for API-based ML engines
docstr: Retrieve API key from environment variables
code: def get_api_key(env_var: str):
      """Retrieve API key from environment variables"""
      return os.environ.get(env_var)
  
file_path: mindsdb/tests/unit/ml_handlers/base_ml_test.py
imports: import os
  import time
  import pandas
  from mindsdb_sql import parse_sql
  from ..executor_test_base import BaseExecutorTest
label_desc: Use image node_id 1 for calling the BaseMLAPITest obj's underlying member method code with example usage: obj.get_api_key(env_var) and returns: os