lambda/api/db metrics

def metrics(function, api, start, period):
    """lambda/api/db metrics"""
    from c7n.mu import LambdaManager
    manager = LambdaManager(boto3.Session)
    start = parse_date(start)
    period = int(abs(parse_timedelta(period).total_seconds()))

    print("Lambda Metrics")
    metrics = manager.metrics(
        [{'FunctionName': function}],
        start=start, end=datetime.utcnow(),
        period=period)
    for k in ('Invocations', 'Throttles', 'Errors'):
        values = [n['Sum'] for n in metrics[0][k]]
        render_metrics(k, values)

    if not api:
        return

    print("Api Metrics")
    metrics = gateway_metrics(
        boto3.Session, api, "latest", start, datetime.utcnow(), period)
    for k, data in metrics.items():
        if "Count" in k:
            values = [n['Sum'] for n in data]
        else:
            values = [n['Average'] for n in data]
        render_metrics(k, values)

    print("Db Metrics")
    metrics = db_metrics(
        boto3.Session, "Sphere11.Dev.ResourceLocks",
        start, datetime.utcnow(), period)
    for k, data in metrics.items():
        values = [n['Average'] for n in data]
        render_metrics(k, values)