code: func (c *Context) get(m map[string][]string, key string) (map[string]string, bool) {
  	dicts := make(map[string]string)
  	exist := false
  	for k, v := range m {
  		if i := strings.IndexByte(k, '['); i >= 1 && k[0:i] == key {
  			if j := strings.IndexByte(k[i+1:], ']'); j >= 1 {
  				exist = true
  				dicts[k[i+1:][:j]] = v[0]
  			}
  		}
  	}
  	return dicts, exist
  }
docs: // get is an internal method and returns a map which satisfy conditions.