def METHOD_NAME(self):
    r"""
    Revert what :meth:`hide` does.
    EXAMPLES::
        sage: from sage.features.sagemath import sage__groups
        sage: f = sage__groups()
        sage: f.hide()
        sage: f.is_present()
        FeatureTestResult('sage.groups', False)
        sage: f._features[0].is_present()
        FeatureTestResult('sage.groups.perm_gps.permgroup', False)
        sage: f.unhide()
        sage: f.is_present()    # optional sage.groups
        FeatureTestResult('sage.groups', True)
        sage: f._features[0].is_present() # optional sage.groups
        FeatureTestResult('sage.groups.perm_gps.permgroup', True)
    """
    for f in self._features:
        f.METHOD_NAME()
    super(JoinFeature, self).METHOD_NAME()