code: def from_global_moment_and_saxis(cls, global_moment, saxis):
          
          magmom = Magmom(global_moment)
          return cls(magmom.get_moment(saxis=saxis), saxis=saxis)
docs: Convenience method to initialize Magmom from a given global
          magnetic moment, i.e. magnetic moment with saxis=(0,0,1), and
          provided saxis.
          
          Method is useful if you do not know the components of your
          magnetic moment in frame of your desired saxis.
          
          :param global_moment: 
          :param saxis: desired saxis
          :return: