code: func Temp(f func()) {
  	oenv := env
  	env = map[string]string{}
  	for k, v := range oenv {
  		env[k] = v
  	}
  	defer func() { env = oenv }()
  	f()
  }
docs: // Temp makes a copy of the values and allows operation on
  // those values temporarily during the run of the function.
  // At the end of the function run the copy is discarded and
  // the original values are replaced. This is useful for testing.
  // Warning: This function is NOT safe to use from a goroutine or
  // from code which may access any Get or Set function from a goroutine