Greetings,

Its my first day on Q, so please excuse my noobishness.

I am trying to calculate EMA from 15d window history, but no luck.

# Put any initialization logic here.  The context object will be passed to  
# the other methods in your algorithm.  
def initialize(context):  
    # init  
    set_symbol_lookup_date('2015-01-01')  
    # get data  
    context.stocks = symbols('AAPL', 'TSLA', 'FB', 'NFLX')

# Will be called on every trade event for the securities you specify.  
def handle_data(context, data):  
    for stock in context.stocks:  
        last_15 = history(bar_count = 15, frequency='1d', field='close_price')  
        print last_15[stock]

        ema_15 = ta.EMA(timeperiod=15)  
        print ema_15(last_15[stock])  

        #print ta.EMA(last_15[stock], timeperiod=15)  

This code returns an error:
AttributeError: 'SingleBlockManager' object has no attribute 'itervalues' There was a runtime error on line 18.

While

# Put any initialization logic here.  The context object will be passed to  
# the other methods in your algorithm.  
def initialize(context):  
    # init  
    set_symbol_lookup_date('2015-01-01')  
    # get data  
    context.stocks = symbols('AAPL', 'TSLA', 'FB', 'NFLX')

# Will be called on every trade event for the securities you specify.  
def handle_data(context, data):  
    for stock in context.stocks:  
        last_15 = history(bar_count = 15, frequency='1d', field='close_price')  
        print last_15[stock]

        #ema_15 = ta.EMA(timeperiod=15)  
        #print ema_15(last_15[stock])  

        print ta.EMA(last_15[stock], timeperiod=15)[-1]  

Returns:

TypeError: __init__() got multiple values for keyword argument 'close'  
There was a runtime error on line 21.

Does anyone know what I'm missing here?