def group_platform(db):
    """Group games owned in multiple platforms to one row"""

    temp = db.groupby('Title').agg({'Platform': '; '.join})
    db = db.merge(temp, how='inner', left_on=['Title'], right_on=['Title'])
    db = db.drop('Platform_x', axis=1)
    db = db.drop_duplicates(subset=['Title', 'Platform_y'], keep='last')
    db = db.reset_index(drop=True)
    db = db.rename(columns={"Platform_y": "Platform"})
    return db