custom_generator(arg_generator, firstline):

def main():
    def custom_generator(arg_generator, firstline):
        """This"""
        yield firstline
        for x in arg_generator:
            yield x

    the_data = [1,2,3,4,5]
    firstline = ["BOM"]

    x = custom_generator(the_data, firstline)
    print x

##    for x in custom_generator(the_data, firstline):
##        print x

if __name__ == '__main__':
    main()