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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_filtered_study_ids(shard, include_aliases=False):
 """Optionally filters out aliases from standard doc-id list"""

    from peyotl.phylesystem.helper import DIGIT_PATTERN
    k = shard.get_doc_ids()
    if shard.has_aliases and (not include_aliases):
        x = []
        for i in k:
            if DIGIT_PATTERN.match(i) or ((len(i) > 1) and (i[-2] == '_')):
                pass
            else:
                x.append(i)
        return x