I meant python3-dev... sigh. make deb works now.

debian/control

@@ -7,7 +7,7 @@ Vcs-Git: git://github.com/kamilion/customizer
 Vcs-browser: https://github.com/kamilion/customizer
 Standards-Version: 4.2.0
 X-Python-Version: >= 3.3
-Build-Depends: debhelper (>= 9~), g++, python-dev (>= 3.3~), pyqt5-dev-tools,
+Build-Depends: debhelper (>= 9~), g++, python3-dev (>= 3.3~), pyqt5-dev-tools,
  qttools5-dev-tools
 
 Package: customizer

debian/customizer.postinst.debhelper

@@ -0,0 +1,7 @@
+
+# Automatically added by dh_python3:
+if which py3compile >/dev/null 2>&1; then
+	py3compile -p customizer /usr/share/customizer
+fi
+
+# End automatically added section

debian/customizer.prerm.debhelper

@@ -0,0 +1,10 @@
+
+# Automatically added by dh_python3:
+if which py3clean >/dev/null 2>&1; then
+	py3clean -p customizer 
+else
+	dpkg -L customizer | perl -ne 's,/([^/]*)\.py$,/__pycache__/\1.*, or next; unlink $_ or die $! foreach glob($_)'
+	find /usr/lib/python3/dist-packages/ -type d -name __pycache__ -empty -print0 | xargs --null --no-run-if-empty rmdir
+fi
+
+# End automatically added section