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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_files_recursively(rootdir):
 """Sometimes, we want to use this tool with non-git repositories. This function allows us to do so. """

    output = []
    for root, dirs, files in os.walk(rootdir):
        for filename in files:
            output.append(os.path.join(root, filename))

    return output