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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 _already_cutoff_filtered(in_file, filter_type):
 """Check if we have a pre-existing cutoff-based filter file from previous VQSR failure. """

    filter_file = "%s-filter%s.vcf.gz" % (utils.splitext_plus(in_file)[0], filter_type)
    return utils.file_exists(filter_file)