<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_clusters(pdb_id):
 """Return cluster related web services of given PDB_ID Parameters pdb_id : string A 4 character string giving a pdb entry of interest Returns ------- out : dict A dictionary containing the representative clusters for the specified PDB ID Examples -------- {'pdbChain': {'@name': '2W72.A'}} """

    out = get_info(pdb_id, url_root = 'http://www.rcsb.org/pdb/rest/representatives?structureId=')
    out = to_dict(out)
    return remove_at_sign(out['representatives'])