anchor.diff:  
     postPatch = ''
       substituteInPlace pyproject.toml \
  -     --replace 'importlib-metadata = {version = "^1.6.0", python = "<3.8"}' \
  +      --replace 'importlib-metadata = {version = "^1.6.0", python = "<3.8"}' \
          'importlib-metadata = {version = ">=1.6", python = "<3.8"}' \
  -     --replace 'version = "^21.2.0"' 'version = ">=21.2"'
  +      --replace 'version = "^21.2.0"' 'version = ">=21.2"' \
  +      --replace 'packaging = "^20.4"' 'packaging = "*"'
     '';
   
     nativeBuildInputs = [
  
positive.code:     html5lib
      keyring
      lockfile
      pexpect
      pkginfo
      poetry-core
  
negative.code: , intreehooks
  , keyring
  , lockfile
  , packaging
  , pexpect
  , pkginfo
  , poetry-core
  