def METHOD_NAME(
    script: PipTestEnvironment,
) -> None:
    """
    Installing a different version in user site should uninstall an existing
    different version in user site.
    """
    create_basic_wheel_for_package(script, "base", "1.0.0")
    create_basic_wheel_for_package(script, "base", "2.0.0")
    script.pip(
        "install",
        "--no-cache-dir",
        "--no-index",
        "--find-links",
        script.scratch_path,
        "--user",
        "base==2.0.0",
    )
    result = script.pip(
        "install",
        "--no-cache-dir",
        "--no-index",
        "--find-links",
        script.scratch_path,
        "--user",
        "base==1.0.0",
    )
    base_1_dist_info = script.user_site / "base-1.0.0.dist-info"
    base_2_dist_info = script.user_site / "base-2.0.0.dist-info"
    result.did_create(base_1_dist_info)
    result.did_not_create(base_2_dist_info)