'Set user profile privacy.
Arguments:
privacy (str): \'all_users\' or \'private\''

@privacy.setter
def privacy(self, privacy):

    self.wait_for_element_visibility('select#u-field-select-account_privacy', 'Privacy    dropdown    is    visible')
    if (privacy != self.privacy):
        query = self.q(css=PROFILE_VISIBILITY_INPUT)
        select_option_by_value(query, privacy, focus_out=True)
        EmptyPromise((lambda : (privacy == self.privacy)), 'Privacy    is    set    to    {}'.format(privacy)).fulfill()
        self.wait_for_ajax()
        if (privacy == 'all_users'):
            self.wait_for_public_fields()
