'Set uid and gid.
@param uid: The user ID as whom to execute the process.  If
this is L{None}, no attempt will be made to change the UID.
@param gid: The group ID as whom to execute the process.  If
this is L{None}, no attempt will be made to change the GID.'

def __init__(self, uid=None, gid=None):

    self.uid = uid
    self.gid = gid
