new_contents: import pytest
  
  
  @pytest.fixture
  def credentials():
      """Fake set of MWS credentials"""
      return {
          "access_key": "AAAAAAAAAAAAAAAAAAAA",
          "secret_key": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
          "account_id": "AAAAAAAAAAAAAA",
      }
  
subject: Add fake MWS credentials pytest fixture