Im trying to use RSI in a stratey...always getting the same error:   Runtime Error: NameError : name 'RSI' is not defined

Same issue in the tutorial 200-50 EMA Momentum Universe , if I excange ExponentialMovingAverage with RSI  I get the same error

 

 

class SelectionData():
#3. Update the constructor to accept a history array
def __init__(self,history):
self.slow = RSI(200)
self.fast = ExponentialMovingAverage(50)
#4. Loop over the history data and update the indicators
for bar in history.itertuples():
self.fast.Update(bar.Index[1], bar.close)
self.slow.Update(bar.Index[1], bar.close)

def is_ready(self):
return self.slow.IsReady and self.fast.IsReady

def update(self, time, price):
self.fast.Update(time, price)
self.slow.Update(time, price)

 

https://www.quantconnect.com/terminal/#task-158/Preparing-Indicators-with-History