def book(symbol, token='<STR_LIT>', version='<STR_LIT>'):
_raiseIfNotStr(symbol)<EOL>return _getJson('<STR_LIT>' + symbol + '<STR_LIT>', token, version)<EOL>
Book data

    https://iextrading.com/developer/docs/#book
    realtime during Investors Exchange market hours

    Args:
        symbol (string); Ticker to request
        token (string); Access token
        version (string); API version

    Returns:
        dict: result