Complex quantities in the metainfo

Usually, excited-states calculations have to deal with Green functions which are complex quantities. I was preparing a metainfo schema for this, but complex quantities seem to not be supported in Nomad (please correct me if I am wrong).

Should I simply go with two quantities defined for the same one as x_real and x_imag or is there a simpler way of dealing with this? @mscheidg @lucamghi