def items_to_params(self, items):
        """ evaluate the found items (strings) to become floats, ints or lists. 
        """
        params = {}
        for t,v in items:       
            try:
                # try to evaluate parameter (float, int, list)
                if v in ['grid', 'list']:
                    params[t] = v
                else:
                    params[t] = eval(v)
                if isinstance(params[t], ndarray):
                    params[t] = params[t].tolist()
            except (NameError, SyntaxError):
                # otherwise assume string
                params[t] = v
        return params
evaluate the found items (strings) to become floats, ints or lists.