def _description_columns_json(self, cols=None):
ret = {}<EOL>cols = cols or []<EOL>d = {k: v for (k, v) in self.description_columns.items() if k in cols}<EOL>for key, value in d.items():<EOL><INDENT>ret[key] = as_unicode(_(value).encode("<STR_LIT>"))<EOL><DEDENT>return ret<EOL>
Prepares dict with col descriptions to be JSON serializable