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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_sub_array_ids():
 """Return list of sub-array Id's currently known to SDP"""

    ids = set()
    for key in sorted(DB.keys(pattern='scheduling_block/*')):
        config = json.loads(DB.get(key))
        ids.add(config['sub_array_id'])
    return sorted(list(ids))