Something is nit not quite write. It seams that I'm failing to interate on this example but with a nested struct. This is what I'm trying "str:clientStateclient1": { "str:vec_mapper.len": "1", "str:vec_mapper.item:u32:1": { "1-pull_id": "u32:1", "2-pull_time_stamp_entry": "u64:0", "3-pull_time_stamp_last_collection": "u64:0", "4-pull_amount": "biguint:1,000,000,000,000,000,000,000" } } My error is for key 0x636c69656e745374617465636c69656e7431 (str:clientStateclient1): Want: { "str:vec_mapper.len": "1", "str:vec_mapper.item:u32:1": { "1-pull_id": "u32:1", "2-pull_time_stamp_entry": "u64:0", "3-pull_time_stamp_last_collection": "u64:0", "4-pull_amount": "biguint:1,000,000,000,000,000,000,000" } }. Have: "" for key 0x636c69656e745374617465636c69656e74315f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f2e6c656e (str:clientStateclient1_________________________.len): Want: "". Have: "0x01 (1)" for key 0x636c69656e745374617465636c69656e74315f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f5f2e6974656d00000001 (str:"clientStateclient1_________________________.item\x00\x00\x00\x01"): Want: "". Have: "0x0000000100000000000000000000000000000000000000093635c9adc5dea00000 (str:"\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\t65ɭ\xc5ޠ\x00\x00")" Done. Passed: 1. Failed: 1. Skipped: 0. Particularly for this: (str:clientStateclient1_________________________.len): I do not understand from where the _____ underscrols are appearing?