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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 _exists(filenames):
 """Check if every filename exists. If not, print an error message and remove the item from the list. Parameters filenames : list List of filenames to check for existence. Returns ------- list Filtered list of filenames that exists. """

    exists = []
    for filename in filenames:
        if os.path.isfile(filename):
            exists.append(filename)
        else:
            print('fijibin ERROR missing output file {}'.format(filename))

    return exists