segpy is provided by a third party, which is available at https://github.com/sixty-north/segpy.
In version 2.0.4 or higher, some functions are removed by the developers, causing incompatibility, which is the major motivation of storing the previous version as a local copy.
Version 2.0.2 is used in seislab for segy data i/o.
All credits go to the author(s) of the package segpy

