'Returns the iter associated to the workspace ws_name or None
if not found.'

def get_iter_by_name(self, ws_name):

    for ws_iter in self.valid_ws_iters:
        if self.workspace_model.iter_is_valid(ws_iter):
            if (self.workspace_model[ws_iter][0] == ws_name):
                return ws_iter
    return None
