os.popen varies return type depending on exit status?

[David M. Wilson]

Hi there, on Linux:

   >>> [ type(popen(cmd).close()) for cmd in ( 'true', 'foo' ) ]
   sh: line 1: foo: command not found
   [<type 'NoneType'>, <type 'int'>]


This feels inconsistent to me, and it just bit me because I was
expecting a 0 exit status on success, not None. Does close() return
this for historic reasons?


David.