Python pandas convert CSV upto level "n" nested JSON? - json

Question

I want to convert the csv file into nested json upto n level. I am using below code to get the desired output from this link. But I am getting an error:
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-109-89d84e9a61bf> in <module>()
40 # make a list of keys
41 keys_list = []
---> 42 for item in d['children']:
43 keys_list.append(item['name'])
44
TypeError: 'datetime.date' object has no attribute '__getitem__'
Below is the code:
# CSV 2 flare.json
# convert a csv file to flare.json for use with many D3.js viz's
# This script creates outputs a flare.json file with 2 levels of nesting.
# For additional nested layers, add them in lines 32 - 47
# sample: http://bl.ocks.org/mbostock/1283663
# author: Andrew Heekin
# MIT License
import pandas as pd
import json
df = pd.read_csv('file.csv')
# choose columns to keep, in the desired nested json hierarchical order
df = df[['Group','year','quarter']]
# order in the groupby here matters, it determines the json nesting
# the groupby call makes a pandas series by grouping 'the_parent' and 'the_child', while summing the numerical column 'child_size'
df1 = df.groupby(['Group','year','quarter'])['quarter'].count()
df1 = df1.reset_index(name = "count")
#print df1.head()
# start a new flare.json document
flare = dict()
flare = {"name":"flare", "children": []}
#df1['year'] = [str(yr) for yr in df1['year']]
for line in df1.values:
the_parent = line[0]
the_child = line[1]
child_size = line[2]
# make a list of keys
keys_list = []
for item in d['children']:
keys_list.append(item['name'])
# if 'the_parent' is NOT a key in the flare.json yet, append it
if not the_parent in keys_list:
d['children'].append({"name":the_parent, "children":[{"name":the_child, "size":child_size}]})
# if 'the_parent' IS a key in the flare.json, add a new child to it
else:
d['children'][keys_list.index(the_parent)]['children'].append({"name":the_child, "size":child_size})
flare = d
# export the final result to a json file
with open('flare.json', 'w') as outfile:
json.dump(flare, outfile)
Expected Output in below format:
{
"name": "stock",
"children": [
{"name": "fruits",
"children": [
{"name": "berries",
"children": [
{"count": 20, "name": "blueberry"},
{"count": 70, "name": "cranberry"},
{"count": 96, "name": "raspberry"},
{"count": 140, "name": "strawberry"}]
},
{"name": "citrus",
"children": [
{"count": 20, "name": "grapefruit"},
{"count": 120, "name": "lemon"},
{"count": 50, "name": "orange"}]
},
{"name": "dried fruit",
"children": [
{"count": 25, "name": "dates"},
{"count": 10, "name": "raisins"}]
}]
},
{"name": "vegtables",
"children": [
{"name": "green leaf",
"children": [
{"count": 19, "name": "cress"},
{"count": 18, "name": "spinach"}]
},
{
"name": "legumes",
"children": [
{"count": 27, "name": "beans"},
{"count": 12, "name": "chickpea"}]
}]
}]
}
Could any one please help how to resolve this error.
Thanks