docs: def gnupg_home():
      """Returns appropriate arguments if GNUPGHOME is set"""
      if 'GNUPGHOME' in os.environ:
          gnupghome = os.environ['GNUPGHOME']
          if not os.path.isdir(gnupghome):
              raise CryptoritoError("Invalid GNUPGHOME directory")
  
          return ["--homedir", gnupghome]
      else:
          return []