How to use the nassl._nassl function in nassl

# The goal here to differentiate rejected SSL handshakes (which will
        # raise SSLHandshakeRejected) from random network errors
        
        except socket.error as e:
            for error_msg in self.HANDSHAKE_REJECTED_SOCKET_ERRORS.keys():
                if error_msg in str(e.args):
                    raise SSLHandshakeRejected('TCP - ' + self.HANDSHAKE_REJECTED_SOCKET_ERRORS[error_msg])
            raise # Unknown socket error
        
        except IOError as e:
            if 'Nassl SSL handshake failed' in str(e.args):
                raise SSLHandshakeRejected('TLS - Unexpected EOF')
            raise
        
        except _nassl.OpenSSLError as e:
            clientCertCaList = self.get_client_CA_list()
            if clientCertCaList: # Server wants a client certificate
                raise ClientAuthenticationError(clientCertCaList)
            
            for error_msg in self.HANDSHAKE_REJECTED_SSL_ERRORS.keys():
                if error_msg in str(e.args):
                    raise SSLHandshakeRejected('TLS - ' + self.HANDSHAKE_REJECTED_SSL_ERRORS[error_msg])
                
            raise # Unknown SSL error if we get there            

if args_command_list.key:
            try:
                open(args_command_list.key,"r")
            except:
                raise CommandLineParsingError('Could not open the client private key file "' + str(args_command_list.key) + '"')

            # Try to load the cert and key in OpenSSL
            try:
                sslClient = SslClient()
                sslClient.use_private_key(args_command_list.cert,
                                        args_command_list.certform,
                                        args_command_list.key,
                                        args_command_list.keyform,
                                        args_command_list.keypass)
            except _nassl.OpenSSLError as e:
                if 'bad decrypt' in str(e.args):
                    raise CommandLineParsingError('Could not decrypt the private key. Wrong passphrase ?')
                raise CommandLineParsingError('Could not load the certificate or the private key. Passphrase needed ?')



        # HTTP CONNECT proxy
        shared_settings['https_tunnel_host'] = None
        if args_command_list.https_tunnel:

            # Parse the proxy URL
            parsedUrl = urlparse(args_command_list.https_tunnel)

            if not parsedUrl.netloc:
                raise CommandLineParsingError(
                    'Invalid Proxy URL for --https_tunnel, discarding all tasks.')