code: func (v Values) GetStr(key interface{}) interface{} {
  	if v == nil { return "" }
  	
  	val := v.Get(key)
  	if val == nil { return "" }
  
  	str, ok := val.(string)
  	if !ok { return "" }
  	return str
  }
docs: // GetStr gets the value associated with the given key in string format.
  // If there are no values associated with the key, Get returns an
  // empty string.