I am on macOS High Sierra

The first command (http://macappstore.org/hiera/)

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

looks OK

The 2nd command results in the error:

brew install caskroom/cask/brew-cask

However, as I understand it is not needed now.

The 3rd command results in the error:

brew cask install hiera
==> Satisfying dependencies
==> Downloading https://downloads.puppetlabs.com/mac/hiera-1.3.4.dmg
Already downloaded: /Users/anarinsky/Library/Caches/Homebrew/Cask/hiera--1.3.4.dmg
==> Verifying checksum for Cask hiera
==> Installing Cask hiera
==> Running installer for hiera; your password may be necessary.
==> Package installers may write to any location; options such as -- 
appdir are ignored.
Password: 
==> installer: Package name is hiera-1.3.4
==> installer: Installing at base path /
==> installer: The install failed (The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance.)
==> Purging files for version 1.3.4 of Cask hiera
Error: Command failed to execute!
==> Failed command:
/usr/bin/sudo -E -- /usr/sbin/installer -pkg 
/usr/local/Caskroom/hiera/1.3.4/hiera-1.3.4.pkg -target /

==> Standard Output of failed command:
installer: Package name is hiera-1.3.4
installer: Installing at base path /
installer: The install failed (The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance.)
==> Standard Error of failed command:
==> Exit status of failed command:
#<Process::Status: pid 10228 exit 1>

I suspect that installing at the base path / does not work.