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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 release_readlock(lockdir_name):
 """Release a previously obtained readlock. Parameters lockdir_name : str Name of the previously obtained readlock """

    # Make sure the lock still exists before deleting it
    if os.path.exists(lockdir_name) and os.path.isdir(lockdir_name):
        os.rmdir(lockdir_name)