Dear Cython developers, Python supports meta-programming, in which a variable with name specified in a string can be created at run-time. One built-in library which make use of this is argparse. For example: parser.add_argument('-N', '--max_threads', help='maximum number of concurrent decoding threads', type=int, default=16) in this case, the variable max_threads is created from the string argument. And then Cython will generate an incorrect C program with the following error: smt.py:78:88: undeclared name not builtin: headtail smt.c:1:2: error: #error Do not use this file, it is the result of a failed Cython compilation. In comparison, I found that nuitka can convert this kind of Python programs sucessfully. I hope Cython can be improved. Thanks! Cheers, Xuancong