Doesn't seem to install dependencies correctly

[raxod502]

I tried running

% pipman -S python-hdl-checker

but unfortunately the generated PKGBUILD was as follows

# PKGBUILD generated by pipman
# Python package author: Andre Souto <andre820@gmail.com>
pkgname=python-hdl-checker
pkgver=0.6.13
pkgrel=1
pkgdesc="HDL code checker"
arch=(any)
url="https://github.com/suoto/hdl_checker"
license=(GPLv3)
makedepends=("python" "python-pip")
build() {
  pip install --no-deps --target="hdl-checker" hdl-checker==0.6.13
}
package() {
  sitepackages=$(python -c "import site; print(site.getsitepackages()[0])")
  mkdir -p $pkgdir/"$sitepackages"
  cp -r $srcdir/hdl-checker/* $pkgdir/"$sitepackages"
}

which does not include any of the numerous required dependencies for the package, such as

argcomplete-1.11.1 argparse-1.4.0 bottle-0.12.18 certifi-2019.11.28 chardet-3.0.4 future-0.18.2 hdl-checker-0.6.13 idna-2.7 jedi-0.15.2 parso-0.6.1 pluggy-0.13.1 prettytable-0.7.2 python-jsonrpc-server-0.3.4 python-language-server-0.31.8 requests-2.20.0 tabulate-0.8.6 typing-3.7.4.1 ujson-1.35 urllib3-1.24.3 waitress-1.4.3

which show up in the output of Pipman while building the package, so of course the hdl_checker utility that was installed is completely nonfunctional. My understanding of Pipman was that I could use it to install arbitrary packages from PyPI as Pacman packages, but this doesn't seem to be the case -- have I misunderstood something? If so, what is the use case for this tool?