def METHOD_NAME(db):
    original = VALUE_MAPPINGS["transactions"]["filter_function"]
    VALUE_MAPPINGS["transactions"]["filter_function"] = MagicMock(returned_value="")
    csv_sources = download_generation.get_download_sources(
        {"download_types": ["transactions"], "filters": {"award_type_codes": list(award_type_mapping.keys())}}
    )
    assert len(csv_sources) == 2
    VALUE_MAPPINGS["transactions"]["filter_function"] = original
    assert csv_sources[0].file_type == "d1"
    assert csv_sources[0].source_type == "transactions"
    assert csv_sources[1].file_type == "d2"
    assert csv_sources[1].source_type == "transactions"