Question: I'm trying to study the neural-network-and-deep-learning (http://neuralnetworksanddeeplearning.com/chap1.html). Using the updated version for Python 3 by MichalDanielDobrzanski (https://github.com/MichalDanielDobrzanski/DeepLearningPython). Tried to run it in my command console and it gives an error below. I've tried uninstalling and reinstalling setuptools, theano, and numpy but none have worked thus far. Any help is very appreciated!! Here's the full error log: WARNING (theano.configdefaults): g++ not available, if using conda: `conda install m2w64-toolchain` C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\configdefaults.py:560: UserWarning: DeprecationWarning: there is no c++ compiler.This is deprecated and with Theano 0.11 a c++ compiler will be mandatory warnings.warn("DeprecationWarning: there is no c++ compiler." WARNING (theano.configdefaults): g++ not detected ! Theano will be unable to execute optimized C-implementations (for both CPU and GPU) and will default to Python implementations. Performance will be severely degraded. To remove this warning, set Theano flags cxx to an empty string. Traceback (most recent call last): File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\configparser.py", line 168, in fetch_val_for_key return theano_cfg.get(section, option) File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\configparser.py", line 781, in get d = self._unify_values(section, vars) File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\configparser.py", line 1149, in _unify_values raise NoSectionError(section) from None configparser.NoSectionError: No section: 'blas' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\configparser.py", line 327, in __get__ val_str = fetch_val_for_key(self.fullname, File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\configparser.py", line 172, in fetch_val_for_key raise KeyError(key) KeyError: 'blas.ldflags' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "C:\Users\ASUS\Documents\GitHub\Neural-network-and-deep-learning-but-for-python-3\test.py", line 156, in <module> import network3 File "C:\Users\ASUS\Documents\GitHub\Neural-network-and-deep-learning-but-for-python-3\network3.py", line 37, in <module> import theano File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\__init__.py", line 124, in <module> from theano.scan_module import (scan, map, reduce, foldl, foldr, clone, File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\scan_module\__init__.py", line 41, in <module> from theano.scan_module import scan_opt File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\scan_module\scan_opt.py", line 60, in <module> from theano import tensor, scalar File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\tensor\__init__.py", line 17, in <module> from theano.tensor import blas File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\tensor\blas.py", line 155, in <module> from theano.tensor.blas_headers import blas_header_text File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\tensor\blas_headers.py", line 987, in <module> if not config.blas.ldflags: File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\configparser.py", line 332, in __get__ val_str = self.default() File "C:\Users\ASUS\AppData\Local\Programs\Python\Python39\lib\site-packages\theano\configdefaults.py", line 1284, in default_blas_ldflags blas_info = np.distutils.__config__.blas_opt_info AttributeError: module 'numpy.distutils.__config__' has no attribute 'blas_opt_info' 

Answer: I had the same issue and solved it downgrading numpy to version 1.20.3 by: pip3 install --upgrade numpy==1.20.3