<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_nodes(cluster):
 """Get all the nodes of a given cluster. Args: cluster(string):
 uid of the cluster (e.g 'rennes') """

    gk = get_api_client()
    site = get_cluster_site(cluster)
    return gk.sites[site].clusters[cluster].nodes.list()