Pgadmin4 off - line installation

dear:
I would like to ask how to deploy pgadmin4 to bare metal isolated from the Internet.

Now move the pgadmin4 on the Internet to the bare metal off-grid using the following steps

(pgadmin) [root(at)localhost pgadmin4]# pip3 freeze >requirements.txt
(pgadmin) [root(at)localhost pgadmin4]# pip3 download -r requirements.txt -d /home/pack/

Package the files in the directory /home/pack/ to pack.tar.gz.
Copy pack.tar.gz to the bare metal on the off-net, configure the environment.

Use the following command
pip3 install --no-index --find-links=/home/pack -r requirements.txt
The installation failed.

I want to ask you: The installation steps in the off-network environment? We can think that the operating system in the off-net is centos 7.