text: Title: Volatility indicator returns 0 values
  Body: 
  **Describe the bug**
  I tried to use the volatility indicator but it just returns 0 values. I checked my code if the close column has no value but it has and it's in datatype float so I don't understand why the indicator is giving me 0.0 values. 
  
  **To Reproduce**
  I implemented it like this
  new_d['volatility'] = ta.volatility(new_d['close'], tf='years')
  
  **Expected behavior**
  this is what I expect to return
  https://imgur.com/lopMKFp
  
  **Screenshots**
  If applicable, add screenshots to help explain your problem.
  
  But All I got was this
  https://imgur.com/hnAuyrT
  https://imgur.com/OBeBLSL
  https://imgur.com/ghGb3ea
  
  Thanks in advance for addressing my issue