'List available SSH public keys.
:keyword ex_location: Location (region) used as filter
:type    ex_location: :class:`NodeLocation`
:return: Public keys
:rtype: ``list``of :class:`KeyPair`'

def list_key_pairs(self, ex_location=None):

    action = self._get_project_action('sshkey')
    params = {}
    if ex_location:
        params['region'] = ex_location.id
    response = self.connection.request(action, params=params)
    return self._to_key_pairs(response.object)
