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 add_handles(self, model, forward_handle, backward_handle):
        """
        Add handles to all non-container layers in the model.
        Recursively for non-container layers
        """
        handles_list = []
        model_children = list(model.children())
        if model_children:
            for child in model_children:
                handles_list.extend(self.add_handles(child, forward_handle, backward_handle))
        else:  # leaves
            handles_list.append(model.register_forward_hook(forward_handle))
            handles_list.append(model.register_backward_hook(backward_handle))
        return handles_list