For now the SR Research pylink module is packaged with the Standalone flavours of PsychoPy and can be imported with:
import pylink
You do need to install the Display Software (which they also call Eyelink Developers Kit) for your particular platform. This can be found by following the threads from:
https://www.sr-support.com/forums/forumdisplay.php?f=17
for pylink documentation see:
https://www.sr-support.com/forums/showthread.php?t=14
Performing research with eye-tracking equipment typically requires a long-term investment in software tools to collect, process, and analyze data. Much of this involves real-time data collection, saccadic analysis, calibration routines, and so on. The EyeLink® eye-tracking system is designed to implement most of the required software base for data collection and conversion. It is most powerful when used with the Ethernet link interface, which allows remote control of data collection and real-time data transfer. The PyLink toolkit includes Pylink module, which implements all core EyeLink functions and classes for EyeLink connection and the eyelink graphics, such as the display of camera image, calibration, validation, and drift correct. The EyeLink graphics is currently implemented using Simple Direct Media Layer (SDL: www.libsdl.org).
The Pylink library contains a set of classes and functions, which are used to program experiments on many different platforms, such as MS-DOS, Windows, Linux, and the Macintosh. Some programming standards, such as placement of messages in the EDF file by your experiment, and the use of special data types, have been implemented to allow portability of the development kit across platforms. The standard messages allow general analysis tools such as EDF2ASC converter or EyeLink Data Viewer to process your EDF files.