Nested Json to csv using python (recursion)

Question

I know this question has been asked many times. But I am stuck at one point and not got any proper solution that is why I want some help.

So I have nested JSON structure . I have flatten it using below code which I found here

def flatten_json(y):
out = {}
def flatten(x, name=''):
    if type(x) is dict:
        for a in x:
            flatten(x[a], name + a + '.')
    elif type(x) is list:    
         i = 0
         for a in x:
             flatten(a, name + str(i) + '.')
             i += 1
    else:
        out[name[:-1]] = x
flatten(y)
return out

Everything is perfect but when there is structure like dictionary inside list [{},{}] without key to dictionary. It assigns index to it and I don't want it.

Current Output:

0._id.$oid  0.libId 0.personalinfo.name 0.personalinfo.marks.maths.0    0.personalinfo.marks.physic.1   0.clginfo.certificates.0.cert_name_1    0.clginfo.certificates.0.cert_no_1 0.clginfo.certificates.0.cert_exp_1  0.clginfo.certificates.1.cert_name_2    0.clginfo.certificates.1.cert_no_2  0.clginfo.certificates.0.cert_exp_2

Expected Output:

_id.$oid libId personalinfo.name personalinfo.marks.maths.0 personalinfo.marks.physic.1 clginfo.certificates.cert_name_1.0  clginfo.certificates.cert_no_1.0    clginfo.certificates.cert_exp_1.0   clginfo.certificates.cert_name_2.1 clginfo.certificates.cert_no_2.1 clginfo.certificates.cert_exp_2.1

I am very bad at recursion. So please help with some code it will be more helpful. Thank you in advance!

Input:

[{
"id":
{
    "$oid": "00001"
},
"libId":11111,
"personalinfo":
{
    "Name":"xyz",
    "marks":
    [
        "maths":80,
        "physic":90
        .....
     ]

},
"clginfo"
    { 
        "certificates":
        [
        {
            "cert_name_1":"xxx",
            "cert_no_1":12345,
            "cert_exp.1":"20/2/20202"
        
        },
        {
            "cert_name_2":"xxx",
            "cert_no_2":12345,
            "cert_exp_2":"20/2/20202"
        
        },
        ......//could be up to 10
    ]
}}]