homebrew doesn't exist

Created by: flozano

documentation refers to homebrew installation, but I get:

$ brew install openapi-generator
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 3 taps (homebrew/core, caskroom/versions, caskroom/cask).
==> Updated Formulae
azure-cli                                                              dspdfviewer                                                            presto

Error: No available formula with the name "openapi-generator"
==> Searching for a previously deleted formula (in the last month)...
Warning: homebrew/core is shallow clone. To get complete history run:
  git -C "$(brew --repo homebrew/core)" fetch --unshallow

Error: No previously deleted formula found.
==> Searching for similarly named formulae...
==> Searching local taps...
Error: No similarly named formulae found.
==> Searching taps...
==> Searching taps on GitHub...
Error: No formulae found in taps.