handlers.py 文件源码

def _parse_boolean(self, string):
        """Parse string representing a boolean into Python bool type.

        Supported values match `configparser.ConfigParser.getboolean`.

        """
        trues = ['1', 'yes', 'true', 'on']
        falses = ['0', 'no', 'false', 'off']

        string_lower = string.lower()
        if string_lower in trues:
            return True
        elif string_lower in falses:
            return False
        else:
            import itertools
            import click

            msg = (
                "Error: unrecognized value for --%s flag: %s\n"
                "Supported values (case-insensitive): %s" %
                (self.cli_name, string,
                 ', '.join(itertools.chain(trues, falses)))
            )
            click.secho(msg, err=True, fg='red', bold=True)
            ctx = click.get_current_context()
            ctx.exit(1)