Returns the continuous symmetry measure(s) of site with index isite with respect to the
         perfect coordination environment with mp_symbol. For some environments, a given mp_symbol might not
         be available (if there is no voronoi parameters leading to a number of neighbours corresponding to
         the coordination number of environment mp_symbol). For some environments, a given mp_symbol might
         lead to more than one csm (when two or more different voronoi parameters lead to different neighbours
         but with same number of neighbours).
        :param isite: Index of the site
        :param mp_symbol: MP symbol of the perfect environment for which the csm has to be given
        :return: List of csms for site isite with respect to geometry mp_symbol

def get_csms(self, isite, mp_symbol):
        """
        Returns the continuous symmetry measure(s) of site with index isite with respect to the
         perfect coordination environment with mp_symbol. For some environments, a given mp_symbol might not
         be available (if there is no voronoi parameters leading to a number of neighbours corresponding to
         the coordination number of environment mp_symbol). For some environments, a given mp_symbol might
         lead to more than one csm (when two or more different voronoi parameters lead to different neighbours
         but with same number of neighbours).
        :param isite: Index of the site
        :param mp_symbol: MP symbol of the perfect environment for which the csm has to be given
        :return: List of csms for site isite with respect to geometry mp_symbol
        """
        cn = symbol_cn_mapping[mp_symbol]
        if cn not in self.ce_list[isite]:
            return []
        else:
            return [envs[mp_symbol] for envs in self.ce_list[isite][cn]]