diff --git a/cd.sh b/cd.sh
index 7cd5837..850307c 100644
--- a/cd.sh
+++ b/cd.sh
@@ -581,13 +581,15 @@ ${CD_PYTHON_PACKAGES}"
 
 cd_write_python_module () {
     cd_step "Write Python module"
-    cd_write "${CD_PYTHON_PACKAGES}/env.py" "\
-$(cd_echo CD_OPEN CD_DOWN)
-$(cd_echo CD_VERT CD_SPLT)
-$(cd_echo CD___UP CD_SHUT)
-
-$(cd_echo CD_OS_ID CD_OS_VERSION)
-
+    for cd_write_python_module__variable \
+    in OPEN DOWN VERT SPLT __UP SHUT OS_ID OS_VERSION ; do
+        cd_write_python_module__value="\
+$(cd_echo "CD_${cd_write_python_module__variable}")"
+        cd_write_python_module__text="${cd_write_python_module__text}\
+${cd_write_python_module__value}
+"
+    done
+    cd_write "${CD_PYTHON_PACKAGES}/env.py" "${cd_write_python_module__text}\
 CD_STEP = $((CD_STEP+1))
 "
 }