diff --git a/roles/wsgi_website/tasks/main.yml b/roles/wsgi_website/tasks/main.yml
index 4bdf2c97fbe00c8791c838f02b022901a17587eb..25cb1591c053f9ecba153133beb85db5bb185a85 100644
--- a/roles/wsgi_website/tasks/main.yml
+++ b/roles/wsgi_website/tasks/main.yml
@@ -176,7 +176,7 @@
   with_items:
     - package: gunicorn
       version: "{{ gunicorn_version }}"
-  when: "not wsgi_requirements"
+  when: wsgi_requirements | length == 0
   register: install_wsgi_server
   notify:
     - Restart WSGI services
@@ -192,13 +192,13 @@
   with_items:
     - package: futures
       version: "{{ futures_version }}"
-  when: "not wsgi_requirements"
+  when: wsgi_requirements | length == 0
   register: install_wsgi_server
   notify:
     - Restart WSGI services
 
 - include: requirements.yml
-  when: "wsgi_requirements"
+  when: wsgi_requirements | length > 0
 
 - name: Install additional packages in Python virtual environment
   become: true
@@ -208,7 +208,7 @@
     state: present
     virtualenv: "{{ home }}/virtualenv"
   register: install_additional_packages_in_virtualenv
-  when: "virtualenv_packages"
+  when: virtualenv_packages | length > 0
   notify:
     - Restart WSGI services