code: def go_env(self, gopath=None):
      
      # Forcibly nullify the GOPATH if the command does not need one - this can prevent bad user
      # GOPATHs from erroring out commands; see: https://github.com/pantsbuild/pants/issues/2321.
      # NB: As of go 1.8, when GOPATH is unset (set to ''), it defaults to ~/go (assuming HOME is
      # set - and we can't unset that since it might legitimately be used by the subcommand); so we
      # set the GOPATH here to a valid value that nonetheless will fail to work if GOPATH is
      # actually used by the subcommand.
      no_gopath = os.devnull
      return OrderedDict(GOROOT=self.goroot, GOPATH=gopath or no_gopath)
docs: Return an env dict that represents a proper Go environment mapping for this distribution.