Standard imports for Cluster Resolvers.
class ClusterResolver: Abstract class for all implementations of ClusterResolvers.
class GceClusterResolver: Cluster Resolver for Google Compute Engine.
class SimpleClusterResolver: Simple implementation of ClusterResolver that accepts a ClusterSpec.
class TPUClusterResolver: Cluster Resolver for Google Cloud TPUs.
class UnionClusterResolver: Performs a union on underlying ClusterResolvers.