def find_in_compressed(peak_start, compressed_depths, search_start_index):
    """Finds the location of the start of a given peak in the compressed depth file. This method also can be called multiple times in a row, with an increasing search start index to reduce runtime of this method

    Args:
        peak_start (int): the position of the start of the given peak that would be found
        compressed_depths (Dictionary): a position_start, position_end : read_depth formated dictionary of depths 
        search_start_index (int): the index in which to begin the start. This is generally the last found index from the previous search to decrease runtime

    Returns:
        [type]: [description]
    """
    keys = list(compressed_depths.keys())
    for index in range(search_start_index, len(keys)):
        key_start, key_end = keys[index]
        if key_start == peak_start or key_end == peak_start:
            return index
    return -1