For the error message, it describes as 'Unable to sign SAML assertion. It is likely that this server does not have xmlsec1 installed or this is the result of misconfiguration. Reason %(reason)s.' It's clear enough. So maybe we should not override the SAMLSigningError error message for the OSError.
Not sure what error code is better.
For the error message, it describes as 'Unable to sign SAML assertion. It is likely that this server does not have xmlsec1 installed or this is the result of misconfiguration. Reason %(reason)s.' It's clear enough. So maybe we should not override the SAMLSigningError error message for the OSError.