def freeze(h, output_yaml, resolve, groups):
    """Output installed packages."""
    if not groups:
        groups = filter(lambda group: not group.lower().startswith("bower"),
                        h.requirements.keys())
    else:
        groups = [text_type.strip(group) for group in groups.split(",")]

    if output_yaml:
        for requirements in h.requirements.values():
            for requirement in requirements:
                if resolve and not requirement.version:
                    requirement.load_installed_version()
        click.echo(h.requirements.yaml)
    else:
        for group in groups:
            if not h.requirements[group]:
                continue
            click.echo("# {}".format(group))
            for requirement in h.requirements[group]:
                if resolve and not requirement.version:
                    requirement.load_installed_version()
                click.echo(str(requirement))
def _format_unhandled_exception_log(cls, exc, tb, add_newline, should_print_backtrace):
        exc_type = type(exc)
        exception_full_name = "{}.{}".format(exc_type.__module__, exc_type.__name__)
        exception_message = str(exc) if exc else "(no message)"
        maybe_newline = "\n" if add_newline else ""
        return cls._UNHANDLED_EXCEPTION_LOG_FORMAT.format(
            exception_type=exception_full_name,
            backtrace=cls._format_traceback(
                traceback_lines=traceback.format_tb(tb),
                should_print_backtrace=should_print_backtrace,
            ),
            exception_message=exception_message,
            maybe_newline=maybe_newline,
        )