human
What is a the Python code you requested given the following:
Complete the below
@snippet
def metric_crud(client, to_delete):

    ''''Metric CRUD.'
    '''
assistant
#Here is the Python code you requested.
    METRIC_NAME = ('robots-%d' % (_millis(),))
    DESCRIPTION = 'Robots    all    up    in    your    server'
    FILTER = 'logName:apache-access    AND    textPayload:robot'
    UPDATED_FILTER = 'textPayload:robot'
    UPDATED_DESCRIPTION = 'Danger,    Will    Robinson!'
    for metric in client.list_metrics():
        do_something_with(metric)
    metric = client.metric(METRIC_NAME, filter_=FILTER, description=DESCRIPTION)
    assert (not metric.exists())
    metric.create()
    assert metric.exists()
    to_delete.append(metric)
    existing_metric = client.metric(METRIC_NAME)
    existing_metric.reload()
    assert (existing_metric.filter_ == FILTER)
    assert (existing_metric.description == DESCRIPTION)
    existing_metric.filter_ = UPDATED_FILTER
    existing_metric.description = UPDATED_DESCRIPTION
    existing_metric.update()
    existing_metric.reload()
    assert (existing_metric.filter_ == UPDATED_FILTER)
    assert (existing_metric.description == UPDATED_DESCRIPTION)
    def _metric_delete():
        metric.delete()
    _backoff_not_found(_metric_delete)
    to_delete.remove(metric)