Error: Issue the certificates on the blockchain

Issue the certificates on the blockchain

bash-4.3# cert-issuer -c /etc/cert-issuer/conf.ini
WARNING - Your app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
INFO - This run will try to issue on the bitcoin_regtest chain
INFO - Set cost constants to recommended_tx_fee=0.000600,min_per_output=0.000028,satoshi_per_byte=250
INFO - Processing 0 certificates
INFO - Total cost will be 133500 satoshis
Traceback (most recent call last):
File “/usr/bin/cert-issuer”, line 11, in
load_entry_point(‘cert-issuer==2.0.22’, ‘console_scripts’, ‘cert-issuer’)()
File “/usr/lib/python3.6/site-packages/cert_issuer/main.py”, line 17, in cert_issuer_main
issue_certificates.main(parsed_config)
File “/usr/lib/python3.6/site-packages/cert_issuer/issue_certificates.py”, line 36, in main
return issue(app_config, certificate_batch_handler, transaction_handler)
File “/usr/lib/python3.6/site-packages/cert_issuer/issue_certificates.py”, line 22, in issue
tx_id = issuer.issue(app_config.chain)
File “/usr/lib/python3.6/site-packages/cert_issuer/issuer.py”, line 23, in issue
blockchain_bytes = self.certificate_batch_handler.prepare_batch()
File “/usr/lib/python3.6/site-packages/cert_issuer/certificate_handlers.py”, line 101, in prepare_batch
for _, metadata in self.certificates_to_issue.items():
AttributeError: ‘CertificateBatchHandler’ object has no attribute ‘certificates_to_issue’

I’m trying to resolve the issue from yesterday but still not found the issue.

Anyone who is experienced this please suggest where I’m making the mistakes.