def n_tasks(dec_num):
    """
    Takes a decimal number as input and returns the number of ones in the
    binary representation.
    This translates to the number of tasks being done by an organism with a
    phenotype represented as a decimal number.
    """
    bitstring = ""
    try:
        bitstring = dec_num[2:]
    except:
        bitstring = bin(int(dec_num))[2:]  # cut off 0b
    # print bin(int(dec_num)), bitstring
    return bitstring.count("1")