code: func (e *Env) RemoveMatch(fn func(k, v string) bool) {
  	e.iterate(func(realKey, k, v string) bool {
  		if fn(k, v) {
  			delete(e.env, realKey)
  		}
  		return true
  	})
  }
docs: // RemoveMatch iterates over all keys and values in the environment, invoking
  // the callback function, fn, for each key/value pair. If fn returns true, the
  // key is removed from the environment.