code: def list_elasticache(region, filter_by_kwargs):
      
      conn = boto.elasticache.connect_to_region(region)
      req = conn.describe_cache_clusters()
      data = req["DescribeCacheClustersResponse"]["DescribeCacheClustersResult"]["CacheClusters"]
      if filter_by_kwargs:
          clusters = [x['CacheClusterId'] for x in data if x[filter_by_kwargs.keys()[0]] == filter_by_kwargs.values()[0]]
      else:
          clusters = [x['CacheClusterId'] for x in data]
      return clusters
docs: List all ElastiCache Clusters.