def METHOD_NAME(context: click.Context, mounts: list[str]) -> None:
    """
    Add a bind-mounted folder
    The bind-mounted folder will be added to the project configuration, in the ``MOUNTS``
    setting.
    Values passed to this command can take one of two forms. The first is explicit::
        tutor mounts add myservice:/host/path:/container/path
    The second is implicit::
        tutor mounts add /host/path
    With the explicit form, the value means "bind-mount the host folder /host/path to
    /container/path in the "myservice" container at run time".
    With the implicit form, plugins are in charge of automatically detecting in which
    containers and locations the /host/path folder should be bind-mounted. In this case,
    folders can be bind-mounted at build-time -- which cannot be achieved with the
    explicit form.
    """
    new_mounts = []
    for mount in mounts:
        if not bindmount.parse_explicit_mount(mount):
            # Path is implicit: check that this path is valid
            # (we don't try to validate explicit mounts)
            mount = os.path.abspath(os.path.expanduser(mount))
            if not os.path.exists(mount):
                raise exceptions.TutorError(f"Path {mount} does not exist on the host")
        new_mounts.append(mount)
        fmt.echo_info(f"Adding bind-mount: {mount}")
    context.invoke(config_save, append_vars=[("MOUNTS", mount) for mount in new_mounts])