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 _from_python(self, key, value):
        new_path = self._path + (key,)
        if isinstance(value, dict):
            value = self.custom_classes.get(new_path, ConfigDict)(value, new_path)
        elif isinstance(value, list):
            value = self.custom_classes.get(new_path, ConfigList)(value, new_path)
        elif isinstance(value, str):
            match = self.PROXY_VAR_RE.match(value)
            if match:
                value = self._make_proxy(key, match)
        return value