I am brand new here, but I LOVE the platform. Trying to get my feet wet and figure my way around.  I am trying to pull monthly historical option prices for SPY into the research tool to try some backtesting.  However, I am not understanding how the months are filtered out.  When I request history from June 1, 2017,  I get the following months: Jun, Jul, Aug, Sep, Dec, Jan, Mar  But when I request history from Sep 1, 2017, then I get:  Aug, Sep, Oct, Nov, Dec, Jun, Jul   I dont understand why I am getting those months, how do I get _all_ the months from Jun 1, 2017? 

2nd question:  the last cell of the notebook will hang and the kernel will eventually die.  Any ideas? 

Really appreciate the help! Really excited to get started here!