Constructing MongoDB document from a dict with character code-to-integer translation

I have an class definition:

class ScoreDetail(Document):
    location            = StringField(help_text = "province")
    school              = StringField(help_text = "school")
    spec                = StringField(help_text = "major")
    bz                  = IntField(help_text = "1: Bachelor, 2: Academy, 0: exception")
    wl                  = IntField(help_text = "1: w, 2: l, 0: exception")
    batch               = StringField(help_text = "batch")
    score               = IntField(help_text = "score")
    average_score       = FloatField(help_text = "average score")
    average_score_rank  = FloatField(help_text = "rank of average score")
    low_score           = IntField(help_text = "the lowest score")
    low_score_rank      = IntField(help_text = "rank of the lowest score")
    high_score          = IntField(help_text = "highest score")
    high_score_rank     = IntField(help_text = "rank of the highest score")
    score_number        = IntField(help_text = "people in this score")
    spec_number         = IntField(help_text = "people in the major")
    rank                = IntField(help_text = "rank")
    year                = IntField('year')

Now I have a dict named item, like this:

{
  "school": u"Peking University",
  "average_score": u"255",
  "low_score_rank": u"195466",
  "wl": u"w",
  "batch": u"4",
  "score_number": u"1",
  "average_score_rank": u"178199",
  "low_score": u"150",
  "high_score": u"464",
  "score": u"150",
  "spec_number": u"62",
  "rank": u"195466",
  "year": u"14",
  "high_score_rank": u"60631",
  "spec": u"E-commerce",
  "bz": u"z",
  "location": u"US"
}

I want construct a ScoreDetail object from this dict, so I do this:

wl_map = {'w': 1, 'l': 2}
bz_map = {'b': 1, 'z': 2}
item['wl'] = wl_map[item['wl']]
item['year'] = '20' + item['year']
item['bz'] = bz_map[item['bz']]

s = ScoreDetail(
        school=item['school'],
        average_score=item['average_score'],
        low_score_rank=item['low_score_rank'],
        wl=item['wl'],
        batch=item['batch'],
        score_number=item['score_number'],
        average_score_rank=item['average_score_rank'],
        low_score=item['low_score'],
        high_score=item['high_score'],
        score=item['score'],
        spec_number=item['spec_number'],
        rank=item['rank'],
        year=item['year'],
        high_score_rank=item['high_score_rank'],
        spec=item['spec'],
        bz=item['bz'],
        location=item['location']
        )

Now I want to know these two things:

1. Can I simplify this code?
2. As you can see, this is a mongoengine schema. It inherits Document, so it can make '1' to int, '150' to float as default, but if I were not to use MongoEngine, this is just a common class. How can I make some type conversion as default?