No pre-season box scores?
Issue No. 202
Quoting directly from /api/methods/mlb-box-score
This method returns the box score for an MLB game. Box scores are available for regular and postseason games.
The recommended way of downloading box scores is in conjunction with the Events method. For each Event, check its event_status for completed and season_type for either regular or post. When these values are true, the box score is available to download.
for each event in events:
if event_status is completed and season_type is regular or post:
get box score