Hi, Has anyone had luck with creating certificate object for azure automation runbooks ...keep failing while trying to load the base64 cert

with open('cert.cer'], 'rb') as auto_cert:
    automation_certificate_content = auto_cert.read()

automation_certificate = automation.Certificate(
    config_bie['certificate']['name'],
    name=config_bie['certificate']['name'],
    description=config_bie['certificate']['description'],
    base64=automation_certificate_content_base64, # fails here
    resource_group_name=rgazautopbie.name,
    automation_account_name=automation_account.name
)