'Get a list of keypairs.
:param user_id: Id of key-pairs owner (Admin only).'

@api_versions.wraps('2.10', '2.34')
def list(self, user_id=None):

    query_string = (('?user_id=%s' % user_id) if user_id else '')
    url = ('/%s%s' % (self.keypair_prefix, query_string))
    return self._list(url, 'keypairs')
