How to remove null objects of whois results - string

Question

I use the python-whois module.
I have this code:
for whoisInfo in domainWhoisInfo :
stringWhoisInfo = str(stringWhoisInfo) + str(whoisInfo) + "\n\n"
domainWhoisInfo => array which contains whois data of each domain
stringWhoisInfo => string which concatenate whois data of all domains
I concatenate whois results of many domain name in a string.
And When I store these results in a log file I get the
following output :
{
"updated_date": null,
"status": null,
"name": null,
"dnssec": null,
"city": null,
"expiration_date": null,
"zipcode": null,
"domain_name": null,
"country": null,
"whois_server": null,
"state": null,
"registrar": null,
"referral_url": null,
"address": null,
"name_servers": null,
"org": null,
"creation_date": null,
"emails": null
}
{
"updated_date": null,
"status": [
"clientDeleteProhibited -- http://www.icann.org/epp#clientDeleteProhibited",
"clientTransferProhibited -- http://www.icann.org/epp#clientTransferProhibited",
"serverTransferProhibited -- http://www.icann.org/epp#serverTransferProhibited"
],
"name": "Panayiotis Yianni",
"dnssec": null,
"city": "Enfield",
"expiration_date": "2017-03-06 23:25:46",
"zipcode": "EN3 7FY",
"domain_name": "AMON.PRO",
"country": "GB",
"whois_server": null,
"state": "London, City of",
"registrar": "OVH (R2367-PRO)",
"referral_url": null,
"address": null,
"name_servers": [
"DNS200.ANYCAST.ME",
"NS200.ANYCAST.ME"
],
"org": "Amon Interactive Ltd",
"creation_date": null,
"emails": [
"panayiotisyianni#live.com",
"panayiotis#amon.pro"
]
}
{
"updated_date": null,
"status": null,
"name": null,
"dnssec": null,
"city": null,
"expiration_date": null,
"zipcode": null,
"domain_name": null,
"country": null,
"whois_server": null,
"state": null,
"registrar": null,
"referral_url": null,
"address": null,
"name_servers": null,
"org": null,
"creation_date": null,
"emails": null
}
I am looking for deleting the whois results which are null
from my string.
And get finally only this output :
{
"updated_date": null,
"status": [
"clientDeleteProhibited -- http://www.icann.org/epp#clientDeleteProhibited",
"clientTransferProhibited -- http://www.icann.org/epp#clientTransferProhibited",
"serverTransferProhibited -- http://www.icann.org/epp#serverTransferProhibited"
],
"name": "Panayiotis Yianni",
"dnssec": null,
"city": "Enfield",
"expiration_date": "2017-03-06 23:25:46",
"zipcode": "EN3 7FY",
"domain_name": "AMON.PRO",
"country": "GB",
"whois_server": null,
"state": "London, City of",
"registrar": "OVH (R2367-PRO)",
"referral_url": null,
"address": null,
"name_servers": [
"DNS200.ANYCAST.ME",
"NS200.ANYCAST.ME"
],
"org": "Amon Interactive Ltd",
"creation_date": null,
"emails": [
"panayiotisyianni#live.com",
"panayiotis#amon.pro"
]
}