[
  { proxy_principals  : { users  : [ "user0_1"] },
    target_principals : { users  : ["*"] } },
  { proxy_principals  : { users  : [ "user2_1"] },
    target_principals : { users  : ["user3_1"], groups : ["group2_1"] } },
  { proxy_principals  : { users  : ["user4_1"] },
    target_principals : { users  : ["user1_1", "user3_1"] } },
  { proxy_principals  : { groups : ["group5_1"] },
    target_principals : { groups : ["group4_2"] } },
  { proxy_principals  : { groups : ["group5_2"] },
    target_principals : { users  : ["user0_2", "user1_2"] } },
  { proxy_principals  : { users  : ["user3_2"] },
    target_principals : { groups : ["group3_2", "group1_2"] } }
]