code: def get_access_token(
      username="johndoe", password="secret", scope=None
  ):
      data = {"username": username, "password": password}
      if scope:
          data["scope"] = scope
      response = client.post("/token", data=data)
      content = response.json()
      access_token = content.get("access_token")
      return access_token
  
imports: from dirty_equals import IsDict, IsOneOf
  from fastapi.testclient import TestClient
  from docs_src.security.tutorial005 import app, create_access_token, fake_users_db, get_password_hash, verify_password
label_desc: Use image node_id 1 for calling a global function with example usage: get_access_token(username, password, scope) and returns: access_token