Hi,

This is (hopefully) a simple python, pandas, or numpy question. I built a custom factor that returns some macroeconomic data. When I try to use it in pipeline I attempt to do some simple math on it (multiply it by 2) but I get an error:

TypeError: unsupported operand type(s) for *: 'int' and 'Slice'  

The offending line is this:

valid_price = price >= 2 * my_custom_factor_slice  

Can someone please point out what I'm doing wrong and how to do this math correctly?

Thanks,
Brett

Here's the custom factor and pipeline code:

class custom_factor_data(CustomFactor):  
    """  
    Custom factor to generate which looks like a self serve data factor  
    Just return a different number depending on the year  
    """  
    window_length = 1  
    # The factor needs an input but this is ignored.  
    inputs = [USEquityPricing.close]  
    # Associate this factor with the SPY asset  
    mask = StaticAssets(symbols(['SPY']))  
    def compute(self, today, assets, out, value):  
        # Make a dictionary with year as the key, and some macro data as the value  
        custom_factor_data_dict = {2018:100.0, 2019:150.0}  
        # Returns a different number depending on the year  
        out[:] = custom_factor_data_dict[today.year]

def make_pipeline():  
    # However, for testing and speed one may want to limit to a much smaller set  
    universe = Q500US()  
    # Create the custom factor and get its slice  
    my_custom_factor_data = custom_factor_data()  
    my_custom_factor_slice = my_custom_factor_data[symbols('SPY')]

    price = USEquityPricing.close.latest

    # This works but the one below generates an error  
    #valid_price = price >= my_custom_factor_slice  
    # This generates an error: TypeError: unsupported operand type(s) for *: 'int' and 'Slice'  
    # How do I multiply the value of the slice by an integer?  
    valid_price = price >= 2 * my_custom_factor_slice

    # Create the pipeline with columns for all our factors  
    pipe = pipe = Pipeline(  
        columns = {  
        'price' : price,  
        'valid_price': valid_price  
        },  
        screen = universe  
     )  
    return pipe