iocp.cb_func assignment bug

[make-github-pseudonymous-again]

iocp (integer optimization control parameters) callback function assignment is not working with cython functions.

Traceback (most recent call last):
  File "./solve", line 5, in <module>
    main.solve( )
  File "src/main.py", line 340, in src.main.solve (src/main.c:9014)
    affectations = args.allocator( args , problem , affectations )
  File "src/main.py", line 135, in src.main.dtcntr (src/main.c:4584)
    datacenter.solve( D , N , R , P , lp , cb = cb )
  File "src/datacenter.py", line 176, in src.datacenter.solve (src/datacenter.c:6889)
    if cb : iocp.cb_func = cb
TypeError: Argument 'callback' has incorrect type (expected ecyglpki.CallbackFunction, got cython_function_or_method)