code: def test_metadata_per_bind(app: Flask, model_class: t.Any) -> None:
      app.config["SQLALCHEMY_BINDS"] = {"a": "sqlite://"}
      db = SQLAlchemy(app, model_class=model_class)
      assert db.metadatas["a"] is not db.metadata
      assert db.metadatas["a"].info["bind_key"] == "a"
  
imports: from __future__ import annotations
  import typing
  import pytest
  import sqlalchemy
  import sqlalchemy.exc
  import sqlalchemy.orm
  from flask import Flask
  from flask_sqlalchemy import SQLAlchemy
  from flask_sqlalchemy.model import DefaultMeta
  from flask_sqlalchemy.model import Model
label_desc: Use image node_id 7 for calling a global function with example usage: test_metadata_per_bind(app, model_class) without return types