'Gets or or more 7-mode Data ONTAP performance counters.'

def get_performance_counters(self, object_name, instance_names, counter_names):

    api_args = {'objectname': object_name, 'instances': [{'instance': instance} for instance in instance_names], 'counters': [{'counter': counter} for counter in counter_names]}
    result = self.send_request('perf-object-get-instances', api_args, enable_tunneling=False)
    counter_data = []
    timestamp = result.get_child_content('timestamp')
    instances = (result.get_child_by_name('instances') or netapp_api.NaElement('None'))
    for instance in instances.get_children():
        instance_name = instance.get_child_content('name')
        counters = (instance.get_child_by_name('counters') or netapp_api.NaElement('None'))
        for counter in counters.get_children():
            counter_name = counter.get_child_content('name')
            counter_value = counter.get_child_content('value')
            counter_data.append({'instance-name': instance_name, 'timestamp': timestamp, counter_name: counter_value})
    return counter_data
