code: func (c *Config) GetInt64(key string) (i int64, err error) {
  	val, ok := (*c)[key]
  	if !ok {
  		return 0, ErrNoSuchKey
  	}
  	switch val.(type) {
  	case int8:
  		return int64(val.(int8)), nil
  	case int16:
  		return int64(val.(int16)), nil
  	case int:
  		return int64(val.(int)), nil
  	case int32:
  		return int64(val.(int32)), nil
  	case int64:
  		return val.(int64), nil
  	case float64:
  		// json loads float64 so handle that case
  		return int64(val.(float64)), nil
  	default:
  		return 0, fmt.Errorf("Wrong type for %s (Type:%T Expecting:%T)", key, val, i)
  	}
  }
docs: // GetInt64 gets the value associated to a key as int64
  // return (int64, error)