import.py

@dataclass
class ImportRecordSchema:
   ...
    
class ImportRecord:
    def __init__(self, **data):
        self.data = ImportRecordSchema(data)
        self.validate() # include promise item check, or raise exceptions
        self.edition_key = self.find_matching_edition()
        self.edition = self.edition_key and web.ctx.site.get(self.edition_key)
        self.work_key = self.edition and self.edition.works[0].key 
        self.work = self.edition.works[0] if self.work_key else new_work(self.edition.dict(), self.data)
        if not work_key:
            self.edition.works = [{'key': self.work['key']}]

        # this is where the business happens
        fix_author_redirects()
        update_edition_with_rec_data()
        update_work_with_rec_data()
            
    def validate(self):
        ...
  
    def find_matching_edition(self):
        ...

    def create(self, account_key=None):
        """i.e. load_data"""
        ...

    def load(self):
        """Updates the record's work and edition with data in the record
        """
        ...

    def has_edition_mods(self):
        """edition in db v. self's modified self.edition"""
        original_edition = web.ctx.site.get(self.edition_key)
        return original_edition == self.edition

    def has_work_mods(self):
        """work in the db v. self's modified self.work"""
        original_work = self.work_key and web.ctx.site.get(self.work_key)
        return original_work == self.work
 
      
def import(rec, account_key=None):
    r = ImportRecord(**rec) # performs normalize

    if not r.edition:
        return r.create(account_key=account_key)

    has_work_mods, has_edition_mods = r.has_edition_mods(), r.has_work_mods()

    edits = [
      i for (i, modified) in
      [(r.edition, has_edition_mods), (r.work, has_work_mods)]
      if modified
    ]
    if edits:
        web.ctx.site.save_many(
            edits, comment='import existing book', action='edit-book'
        )
    return {
        'success': True,
        'edition': {
          'key': r.edition_key,
          'status': 'matched' if has_edition_mods else 'created',
        },
        'work': {
          'key': r.work_key,
          'status': 'matched' if has_work_mods else 'created'
        },
    }