What am I doing wrong?

[Scott David Daniels]

keithlackey wrote:
> I'm relatively new to python and I've run into this problem.
This has two very standard mistakes:
First, as noted by Sybren, messages should just use spaces in order to 
be readable.

After correcting that one:
>    class structure:
>        def __init__(self, folders = []):
>            self.folders = folders
 >    ...

Here is the second one.  Default args are not rebuilt, but shared.
The correct way to do this is:
      class structure:
          def __init__(self, folders=None):
              if folders is None:
                  self.folders = []
              else:
                  self.folders = folders
      ...

--Scott David Daniels
Scott.Daniels at Acm.Org