def get_zero_regions(signal, num_repetitions=2):
    """
    A function to get the zwero regions of a signal. This is useful for selecting the regions that were zero-ed during
    anonymisation.

    :param signal: 
    :param num_repetitions:
    :return: 
    """
    indices = []
    i = 0

    while i < len(signal) - 1:

        start_index = i

        while i < len(signal) - 1 and signal[i] == signal[i + 1] and signal[i] == 0:
            i = i + 1

        end_index = i

        if (start_index != end_index) & (end_index - start_index >= num_repetitions - 1):
            indices.append((start_index, end_index))

        i = i + 1

    return indices