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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 untar_file(tarname, target_dir='.'):
    '''Uncompress a tar file.'''

    o = tarfile.open(tarname, 'r:gz')
    members = o.getmembers()
    for member in members:
        o.extract(member, target_dir)
    o.close()