mod. remove shutil dependency.

Change-Id: I108e78d0b25e02fbb7097e7e46ec1865d1cd4e9c
mod. comments.

Change-Id: I770969245f533beacaed1ddbcf1f8795b03df8da
add. dummy methods for release and finish functions.

Change-Id: Ife75d13612d1d321e25bbf3bf4cc6cb3447f0edb