def season_id(x):
    """takes in 4-digit years and returns API formatted seasonID

    Input Values: YYYY 

    Used in:

    """
    if len(str(x)) == 4:
        try:
            return ''.join(['2', str(x)])
        except ValueError:
            raise ValueError(
                'Enter the four digit year for the first half of the desired season'
                )
    else:
        raise ValueError(
            'Enter the four digit year for the first half of the desired season'
            )
