`regions()` | Returns a list of regions AWS provides their service.
`namespaces()` | Returns a list of namespaces CloudWatch support.
`metrics(namespace)` | Returns a list of metrics in the namespace.
`metrics(namespace, [region])` | Returns a list of metrics in the namespace. (specify region for custom metrics)
`dimension_keys(namespace)` | Returns a list of dimension keys in the namespace.
`dimension_values(region, namespace, metric, dimension_key)` | Returns a list of dimension values matching the specified `region`, `namespace`, `metric` and `dimension_key`.
`ebs_volume_ids(region, instance_id)` | Returns a list of volume id matching the specified `region`, `instance_id`.
