astropy.Table stores columns made of strings (for instance the sfhdelayed.normalise parameter) using the np.str_ type. The issue is that this type is not marshalable, making it impossible to use the modules parameters as keys to cache the partially computed SED in a dictionary. To solve this, rather than using the table directly, we split it into several dictionaries, one for each module. Each dictionary contains the arguments of lists that we convert to the right type.