amoffat/pbs — Issue #27: pbs internal parameters have side effects
Author: fruch
Created: 2012-02-02 17:04:54+00:00
State: open

when doing like this:

```python
from pbs import ls
ls("nonexistent", _err="error.txt")
ls("nonexistent")
```

ls is no dynamic created, and the second ls command will also redirect errors to "error.txt"
this is quite unexpected.

I suggest moving the self.call_args creation from `__init__` to `__call__`