Make sure that a package is not installed.

    name
        The name of the package to uninstall
    user
        The user under which to run pip
    bin_env : None
        the pip executable or virtualenenv to use
    use_vt
        Use VT terminal emulation (see output while installing)

def removed(name,
            requirements=None,
            bin_env=None,
            log=None,
            proxy=None,
            timeout=None,
            user=None,
            cwd=None,
            use_vt=False):
    '''
    Make sure that a package is not installed.

    name
        The name of the package to uninstall
    user
        The user under which to run pip
    bin_env : None
        the pip executable or virtualenenv to use
    use_vt
        Use VT terminal emulation (see output while installing)
    '''
    ret = {'name': name, 'result': None, 'comment': '', 'changes': {}}

    try:
        pip_list = __salt__['pip.list'](bin_env=bin_env, user=user, cwd=cwd)
    except (CommandExecutionError, CommandNotFoundError) as err:
        ret['result'] = False
        ret['comment'] = 'Error uninstalling \'{0}\': {1}'.format(name, err)
        return ret

    if name not in pip_list:
        ret['result'] = True
        ret['comment'] = 'Package is not installed.'
        return ret

    if __opts__['test']:
        ret['result'] = None
        ret['comment'] = 'Package {0} is set to be removed'.format(name)
        return ret

    if __salt__['pip.uninstall'](pkgs=name,
                                 requirements=requirements,
                                 bin_env=bin_env,
                                 log=log,
                                 proxy=proxy,
                                 timeout=timeout,
                                 user=user,
                                 cwd=cwd,
                                 use_vt=use_vt):
        ret['result'] = True
        ret['changes'][name] = 'Removed'
        ret['comment'] = 'Package was successfully removed.'
    else:
        ret['result'] = False
        ret['comment'] = 'Could not remove package.'
    return ret