I would like to process this json data in python:

```
{"data":
   [{"CU":"AGLD","CO": [{"chain":"ERC20"}],                 "fn":"Adventure Gold"}, 
    {"CU":"ACH","CO":  [{"chain":"ERC20"},    {"chain":"BEP20"}],   "fn":"Alchemy"}]}

```

I would like to get the value of all "chain"s. For example like this:

```
CU  chains:
AGLD    ERC20
ACH     ERC20
ACH     BEP20

```

I tried with a for loop, but (in the case of several "chain"s) it returns only the last value of "chain" for example ACH BEP20. Does not return ACH ERC20.