How to use the stacker.util.parse_cloudformation_template function in stacker

def normalize_json(template):
    """Normalize our template for diffing.

    Args:
        template(str): string representing the template

    Returns:
        list: json representation of the parameters
    """
    obj = parse_cloudformation_template(template)
    json_str = json.dumps(
        obj, sort_keys=True, indent=4, default=str, separators=(',', ': '),
    )
    result = []
    lines = json_str.split("\n")
    for line in lines:
        result.append(line + "\n")
    return result

def to_dict(self):
        """Return the template as a python dictionary.

        Returns:
            dict: the loaded template as a python dictionary

        """
        return parse_cloudformation_template(self.rendered)

new_template = stack.blueprint.rendered
        new_stack = normalize_json(new_template)

        output = ["============== Stack: %s ==============" % (stack.name,)]
        # If this is a completely new template dump our params & stack
        if not old_template:
            output.extend(self._build_new_template(new_stack, parameters))
        else:
            # Diff our old & new stack/parameters
            old_template = parse_cloudformation_template(old_template)
            if isinstance(old_template, str):
                # YAML templates returned from CFN need parsing again
                # "AWSTemplateFormatVersion: \"2010-09-09\"\nParam..."
                # ->
                # AWSTemplateFormatVersion: "2010-09-09"
                old_template = parse_cloudformation_template(old_template)
            old_stack = normalize_json(
                json.dumps(old_template,
                           sort_keys=True,
                           indent=4,
                           default=str)
            )
            output.extend(build_stack_changes(stack.name, new_stack, old_stack,
                                              new_params, old_params))
        ui.info('\n' + '\n'.join(output))

        stack.set_outputs(
            provider.get_output_dict(provider_stack))

        return COMPLETE

stack.resolve(self.context, provider)
        # generate our own template & params
        parameters = self.build_parameters(stack)
        new_params = dict()
        for p in parameters:
            new_params[p['ParameterKey']] = p['ParameterValue']
        new_template = stack.blueprint.rendered
        new_stack = normalize_json(new_template)

        output = ["============== Stack: %s ==============" % (stack.name,)]
        # If this is a completely new template dump our params & stack
        if not old_template:
            output.extend(self._build_new_template(new_stack, parameters))
        else:
            # Diff our old & new stack/parameters
            old_template = parse_cloudformation_template(old_template)
            if isinstance(old_template, str):
                # YAML templates returned from CFN need parsing again
                # "AWSTemplateFormatVersion: \"2010-09-09\"\nParam..."
                # ->
                # AWSTemplateFormatVersion: "2010-09-09"
                old_template = parse_cloudformation_template(old_template)
            old_stack = normalize_json(
                json.dumps(old_template,
                           sort_keys=True,
                           indent=4,
                           default=str)
            )
            output.extend(build_stack_changes(stack.name, new_stack, old_stack,
                                              new_params, old_params))
        ui.info('\n' + '\n'.join(output))