Cygdb With Cython 0.14 comes a Cython and Python debugger, its documentation can be viewed here: docs.cython.org/src/userguide/debugging.html. The rest of this document will cover how Cython code could previously be debugged. Symbolic debugging of Cython/Pyrex Code Introduction Generally speaking, a great many bugs in Cython/Pyrex code can be eliminated with simple print statements, or if needing