<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def standard_deviation(data, period):
 """ Standard Deviation. Formula: std = sqrt(avg(abs(x - avg(x))^2)) """

    catch_errors.check_for_period_error(data, period)

    stds = [np.std(data[idx+1-period:idx+1], ddof=1) for idx in range(period-1, len(data))]

    stds = fill_for_noncomputable_vals(data, stds)
    return stds