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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 untrack(context, file_names):
 """Forget about tracking each file in the list file_names Tracking does not create or delete the actual file, it only tells the version control system whether to maintain versions (to keep track) of the file. """

    context.obj.find_repo_type()
    for fn in file_names:
        if context.obj.vc_name == 'git':
            context.obj.call(['git', 'rm', '--cached', fn])
        elif context.obj.vc_name == 'hg':
            context.obj.call(['hg', 'forget', fn])