i clearly don't know how this works

Dockerfile

@@ -6,12 +6,12 @@ COPY requirements.txt .
 
 RUN pip install --no-cache-dir -r requirements.txt
 
-ENV CALDAV_URL=""
-ENV CALENDAR_NAME=""
-ENV USERNAME=""
-ENV PASSWORD=""
-ENV RA_API=""
-ENV RA_USER=""
+ENV CALDAV_URL 
+ENV CALENDAR_NAME 
+ENV USERNAME 
+ENV PASSWORD 
+ENV RA_API 
+ENV RA_USER 
 
 ENTRYPOINT ["sh", "-c"]
 CMD python3 ./app.py "${CALDAV_URL}" "${CALENDAR_NAME}" "${USERNAME}" "${PASSWORD}" "${RA_API}" "${RA_USER}"