def __init__(self, visible=False, timeout=<NUM_LIT:30>, app=None, args=None):
self.app = app or self.create_app(visible, args)<EOL>self.is_terminated = False<EOL>self.status = Status(None)<EOL>self.timeout = timeout<EOL>self.last_host = None<EOL>
Create an emulator instance

`visible` controls which executable will be used.
`timeout` controls the timeout paramater to any Wait() command sent
    to x3270.
`args` allows sending parameters to the emulator executable