'Add extensions to the certificate.
:param extensions: a sequence of X509Extension objects
:return: None'

def add_extensions(self, extensions):

    for ext in extensions:
        if (not isinstance(ext, X509Extension)):
            raise ValueError('One    of    the    elements    is    not    an    X509Extension')
        add_result = _lib.X509_add_ext(self._x509, ext._extension, (-1))
        if (not add_result):
            _raise_current_error()
