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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 getFileSystemSize(dirPath):
 """ Return the free space, and total size of the file system hosting `dirPath`. :param str dirPath: A valid path to a directory. :return: free space and total size of file system :rtype: tuple """

    assert os.path.exists(dirPath)
    diskStats = os.statvfs(dirPath)
    freeSpace = diskStats.f_frsize * diskStats.f_bavail
    diskSize = diskStats.f_frsize * diskStats.f_blocks
    return freeSpace, diskSize