'Return the public key associated with the provided keyname.
:return Key: The ssh public key or ``None`` if it can\'t be determined.'

def get_ssh_key(self):

    try:
        key_pair = self._driver.get_key_pair(self._keyname)
    except Exception as e:
        if ('RequestLimitExceeded' in e.message):
            raise
        raise CloudKeyNotFound('{}:    {}'.format(self._keyname, str(e)))
    if (key_pair.public_key is not None):
        return Key.fromString(key_pair.public_key, type='public_openssh')
    else:
        return None
