'Load a certificate from a X509 object
:param cert: The X509 object
:return: None'

def use_certificate(self, cert):

    if (not isinstance(cert, X509)):
        raise TypeError('cert    must    be    an    X509    instance')
    use_result = _lib.SSL_CTX_use_certificate(self._context, cert._x509)
    if (not use_result):
        _raise_current_error()
