RASA Docker custom channel

when I try cat $PYTHONPATH in container shell I am getting below output:

root@3ed3d3e9875b:/app# cat $PYTHONPATH

cat: /app: Is a directory

when I try env

root@3ed3d3e9875b:/app# env

PYTHONPATH=/app PATH=/opt/venv/bin:/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin