title: Convert JSON file to Pandas dataframe
body: <p>I would like to convert a JSON to Pandas dataframe.</p>
  
  <p>My JSON looks like:
  like:</p>
  
  <pre><code>{ 
     "country1":{ 
        "AdUnit1":{ 
           "floor_price1":{ 
              "feature1":1111,
              "feature2":1112
           },
           "floor_price2":{ 
              "feature1":1121
           }
        },
        "AdUnit2":{ 
           "floor_price1":{ 
              "feature1":1211
           },
           "floor_price2":{ 
              "feature1":1221
           }
        }
     },
     "country2":{ 
        "AdUnit1":{ 
           "floor_price1":{ 
              "feature1":2111,
              "feature2":2112
           }
        }
     }
  }
  </code></pre>
  
  <p>I read the file from GCP using this code:</p>
  
  <pre><code>project = Context.default().project_id
  sample_bucket_name = 'my_bucket'
  sample_bucket_path = 'gs://' + sample_bucket_name
  print('Object: ' + sample_bucket_path + '/json_output.json')
  
  sample_bucket = storage.Bucket(sample_bucket_name)
  sample_bucket.create()
  sample_bucket.exists()
  
  sample_object = sample_bucket.object('json_output.json')
  list(sample_bucket.objects())
  json = sample_object.read_stream()
  </code></pre>
  
  <p>My goal to get Pandas dataframe which looks like:</p>
  
  <p><a href="https://i.stack.imgur.com/NpHNI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NpHNI.png" alt="Given dataframe"></a></p>
  
  <p>I tried using <a href="https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.io.json.json_normalize.html" rel="nofollow noreferrer">json_normalize</a>, but didn't succeed.</p>