pdfmerge-1.0.3 is not a library.
Introduction
This is an interactive CLI PDF merge utility.

Run tool locally
# Clone the repo
cargo build --release
cargo run
Install from apt
sudo add-apt-repository ppa:ani-4nirudh/pdfmerge
sudo apt update
sudo apt install pdfmerge
Build locally
# Make desired changes
cargo build --release
cargo-deb
sudo apt install target/debian/pdfmerge*.deb
Uninstall
sudo apt remove pdfmerge