Returns a list of the implemented coordination geometries with the given coordination number.
        :param coordination: The coordination number of which the list of implemented coordination geometries
        are returned.

def get_not_implemented_geometries(self, coordination=None,
                                       returned='mp_symbol'):
        """
        Returns a list of the implemented coordination geometries with the given coordination number.
        :param coordination: The coordination number of which the list of implemented coordination geometries
        are returned.
        """
        geom = list()
        if coordination is None:
            for gg in self.cg_list:
                if gg.points is None:
                    if returned == 'cg':
                        geom.append(gg)
                    elif returned == 'mp_symbol':
                        geom.append(gg.mp_symbol)
        else:
            for gg in self.cg_list:
                if gg.get_coordination_number() == coordination and gg.points is None:
                    if returned == 'cg':
                        geom.append(gg)
                    elif returned == 'mp_symbol':
                        geom.append(gg.mp_symbol)
        return geom