def setnx(self, name, value):
with self.pipe as pipe:<EOL><INDENT>return pipe.setnx(self.redis_key(name),<EOL>self.valueparse.encode(value))<EOL><DEDENT>
Set the value as a string in the key only if the key doesn't exist.

:param name: str     the name of the redis key
:param value:
:return: Future()