Error in executing Cython script. What to do?

Question

linux

FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! occurs when running cython3 --embed wer.pyx -o reuw.c
when running reuw.c occurs:
reuw.c:4:10: fatal error: Python.h: No such file or directory
#include "Python.h"
^ ~~~~~~~~~
compilation terminated.
I can't figure out what to do with it.