I have a json file (sample below). I am trying to create a Dataframe from this using python:
JSON: 

```
{"data": {
        "A": [{
                "CREATION_DATE": "1482105600",
                "SOURCE_COUNT": "0"
            },
            {
                "CREATION_DATE": "1482105600",
                "SOURCE_COUNT": "0"
            } ],
         "B": [{
                "CREATION_DATE": "1487808000",
                "SOURCE_COUNT": "1048"
                },
                {
                "CREATION_DATE": "1487894400",
                "SOURCE_COUNT": "1103"
                 } ]
         }
 }

```

When I am trying to convert it into a dataframe:

My Code: 

```
import json
file = 'mysample.json'
with open(file) as train_file:
    dict_train = json.load(train_file)

# converting json dataset from dictionary to dataframe
train = pd.DataFrame.from_dict(dict_train, orient='index')
train.reset_index(level=0, inplace=True)

```

Output:

```
    index      A                                                   B
0   data    [{'CREATION_DATE': '1482105600', 'SOURCE_COUNT...   [{'CREATION_DATE': '1487808000', 'SOURCE_COUNT...

```

Instead I am looking to convert this into a dataframe which looks like below:

```
system  CREATION_DATE   SOURCE_COUNT
A        1482105600        0
A        1482105600        0
B        1487808000        1048
B        1487894400        1103

```

How to modify my code to get to the expected output?